Sports watches are evolving. The new TomTom Multi-Sport Cardio wants to be your one-stop shop for all things triathlon. New for TomTom is a built-in heart-rate monitor which means you can abandon the uncomfortable chest strap for real-time monitoring in order to target training zones.

But TomTom isn't the first to make it to this position. We've already seen the likes of the Adidas miCoach Smart Run (and its woeful battery life), while the imminent Samsung Gear Fit also offers a built-in heart-rate monitor.

The big question, then, is whether TomTom is the best offering in this category. We weren't wildly taken by the original Multi-Sport due to various issues - including hard-wired-only data transmission, a loose-fitting watch unit in the strap, and slow GPS lock - so does the TomTom Multi-Sport Cardio represent a company that's listening and learning?

We knew a new TomTom smart watch was on the way. It was inevitable. What we didn't know is how it would be delivered to us.

We were given a meeting time and location in London. Of the many in attendance we were divided into groups and sent on our merry ways in taxis. All pretty normal so far. We were then taken on a bizzare-o journey through London by our "guide" (that's code for actor, but we didn't know until we clocked on) on an adventure that would make Jeremy Beadle proud.

We were confronted by (mock) activists, sent marching up stairs, ended up in a bowling alley, were mocked by a (supposed) taxi office worker, then led through a zombie experiment, before finishing in a spin class headed by Victoria Pendleton.

Yes, really. Like we say: bizarre is the word. But the point of it all was interesting, to see how the Multi-Sport Cardio, when set to "Treadmill" mode, would record our heart rate in response to these events.

But we wanted to use it the Cardio properly. So the moment we got home from the event, we geared up and plonked ourselves on the single speed for a two-wheel dash around London to see what we made of this new watch.

First thing's first: the design, while ultimately similar to its predecessor, is a lot better. The smallest of tweaks can make the biggest of differences, and in the Cardio model TomTom has added a strap with rubber flaps that hold the main watch unit in. The main watch section is removable so it can charge, but with the original model we found it fell out of the strap all too easily. That's not the case any more. If anything it's harder to get back in than it is to take out.

Second there's the heart-rate monitor. It just works. You don't need to be sweaty or lick the contact pads as you would with a chest-based sensor, instead just strap it snugly around a wrist. The system reads heart rate optically, i.e. the two green LED lights can detect fluctuations in blood flow between them and calculate how fast the blood is pumping. Sounds science fiction, but, in general, it worked very well in our on-the-road test.

When the watch is fitted tightly the read seems accurate. This is why we wanted to get out in the real world, hit the pedals hard and sweat some. Even under perspiration the Multi-Sport Cardio's strap holds firmly on the arm. It's surprisingly comfortable too.

It is possible for it to slip out of place, but in an hour-long cycle it was only towards the very end when it slipped a touch too far down the wrist. This led to our apparent heart rate plummeting down to 116bpm when it was clearly much higher. A small anomaly, but easily corrected by repositioning. And you won't be constantly adjusting it because it is not ill-fitting by any means.

If you want it's possible to display exercise zones in real-time - shown as easy, fat burn, endure, speed and sprint; these are based on your age and weight - including the option to target a specific training zone and be alerted when you fall outside of its parameters. A quick vibrate on the wrist is enough to make you look and the visual warning symbol makes it clear what to do next, without taking your eyes off the road for more than a quick glance.

Just like its predecessor the visual language employed by TomTom is easy to grasp. When running you can "ghost run" against your previous course time, for example, and see how much farther ahead or behind you happen to be at any moment. We won't go into this in great detail here as we covered this in our review of the original model, but we'll dig deep into these options again when we come to review the Multi-Sport Cardio in full.

Let's rewind a little first though: before we set off on our ride we wanted to see whether one issue we had with the original watch had been fixed: GPS position tracking. It's not possible to start a GPS-based activity - that's running or cycling; swimming, treadmill and stopwatch options are straightforward recording exercises - before a lock has been acquired. It's still a bit of a problem in the Cardio unfortunately. When in our house it wasn't possible to get a GPS fix at all, but with our Polar RC3 sports watch it was. 

To see the difference in time it took for the TomTom to be GPS-ready we recorded our training session with it and a Polar RC3 on the opposite wrist. By logic we thought the difference would present how much longer it took the TomTom to get a GPS lock. However, the TomTom seemed to think we were around three and a half minutes faster in our complete activity compared to the Polar, but we know for certain it didn't take that much longer to get a GPS lock and begin the activity - it was closer around 30-seconds at an estimate. It does raise the point that these two manufacturer solutions have different timing accuracy.

Either way, the main point is that waiting 30-seconds before you can kick off a training session is a bit annoying; just hanging out there on the spot looking like a lemon. And yes, "QuickGPS" was activated from within the menus to little benefit.

Then there's the data side of things. The original TomTom device required a USB-connected dock to be plugged in to a computer to transmit exercise data. That's still possible, but the inclusion of an iOS app with Bluetooth sync - Android is on its way, but not here yet - means you can automatically ping data to your smart device for upload on the fly. You don't even need to think about it either, as the Multi-Sport Cardio knows when a workout has been recorded and will then look for your previously paired device to send the data to. No more unnecessary plugging in to the computer then.

If you do want to pair manually then you can, of course. The TomTom MySports website is somewhat slow, however, but you're free to use Strava and other solutions as you choose, so picking the TomTom doesn't lock you out of an existing solution, which can only be a good thing.

And that hour long ride? Average speed: 23.3km/h. Average heart rate: 152bpm. Calories burned: 930kcal. We suspect the calories count would actually be higher by some hundreds, but we don't have a cadence monitor fitted so are unable to gauge this statistic. A cadence monitor is available for cycling, but without a built-in one to the watch itself there's no running cadence gauge.

Overall the iOS app is clean, easy to understand and presents all your data without the need to log in to MyTomTom website though, so we would be happy to source it all from here. It's a shame that there's only iOS available for now as we are currently Android users, but just happen to have a spare iPhone on the side for when such techie needs arise.

All this connected tech does, inevitably, cause a less strong battery life. But after an hour of TomTom activities, a further hour of cycling, and some messing around when walking home from the Tube station the battery display is still showing us around three quarters full. Or a quarter empty, depending on your outlook on life.

Our next step will be to thoroughly test the Multi-Sport Cardio, in particular the battery life, over a week or more of use. That's the only way we'll see how it truly holds up.

But what we can certainly say is this: the Cardio model fixes a lot of the moans we had with the original model and the built-in heart-rate monitor is a great thing to have. In fact it's enough to tempt us to make it our go-to cycling sports watch so we can finally be done with the discomfort and chest-chafe from our existing monitor strap.

TomTom has stepped up here. Except, perhaps, with the price: at £279 it's a lot more cash than the original. You get a lot more for the money, but with relevant competition out there already and more incoming it might be a case of wait and see rather than diving in right this second. Nonetheless, we're still impressed with how much better the second-gen product has become in just one year.