Google Maps Navigation for Android 2.0 will not just be setting the cat amongst the pigeons but is probably more akin to handing a rocket launcher to our feline friend as well. From demonstration, the turn by turn satnav system has got several advantages over traditional PND devices from the off but if you need convincing, hereare five reasons why you might want to try it and a few just to make you think again.

One of the problems with satnav devices is that they often rely on outmoded maps usually either supplied by Tele Atlas or Navteq. The trouble is that, not only are these maps slightly inaccurate on purpose, but roads change quite frequently and theses companies can only send round cars to check once every 18 months or so. Recently Google started crowd sourcing corrections much as the OpenStreepMap project does, which means that the internet giant's atlas is going to be more accurate than on any other navigational device. Perhaps it's only a relatively small amount, but take into consideration the updates to way points and business addresses too and it becomes more important. Nothing more frustrating than to drive all the way to a museum to find it's closed or not even there any more.

You don't have to just search for a destination or address but you've got the whole of Google's database to rely on for finding a place you want, and you're not going to find one on any PND as good as that. It's up to date and comprehensive and it'll even search specifically places along the corridor of your route. While most satnavs have a set number of way-points, this system will find you just about anything. If you're looking for a spanner on the way to fix your girlfriend's car, then it'll take you via the appropriate hardware store with just the one you need. Scarily, it's probably the ultimate on the move tool for stalkers for the same reasons too.

This is one of those areas that you really need to have tried out before we know whether it's a boon or not but, potentially, a voice activated satnav is a lot easier and a lot safer while drivers are supposed to be keeping their eyes on the road. You can use it just as you would a Google search and demand the same parameters, even if they're fairly vague - eg: cinema in East London that shows art house films. It'll then direct you to Rich Mix or Rio or any suggestion for the theatre you're after. Naturally, traffic noises, the radio, kids in the back or a poor mic on your handset could completely scupper this one but it's a nice idea. It did also seem to take the phone a little while to register in the demo video but at least it cuts down on finger work for long search enquiries.

While traditional hardware satnavs recently added 3D views to their maps and a few landmarks too, these have only ever been in place for a limited number of roads and cities. GMN can offer a complete set of satellite maps with which you can zoom in to road level detail plus there's also Street View for a few parts of the world to offer drivers an exact picture of what the upcoming junction may look like. You might not use it all the time but that's one feature you just can't compete with.

We were calling for this one for years before the satnav companies finally linked up the traffic reports with route guidance to give us now, not only the shortest journey from A to B but also the fastest as well. The trick here for Google is the way they've shown it on the UI and the fact that it comes at no extra cost as well. The traffic view mode highlights sections of your route in either green, yellow or red depending on how heavy going the conditions are. If you're not happy with what you see, you can get the software to re-route for you.

There's probably quite a bit of egg being wiped off TomTom's faces right now and, if there isn't, it's because the company must be too busy worrying just how it's going to convince consumers to pay the £59 for the mobile app when it launches on Android. It might also tempt a few potential iPhone users away from the platform, but then we all know that that Apple logo doesn't come cheap. The fact is that whatever satnav hardware or other navigation mobile software manufacturers can offer - which is probably going to be a lot less than this Google package anyway - it's going to be next to impossible to beat them on price, and, as a race of thoroughbred cheapskates, that means a lot.

So, Google seems to be right on the money with this but it's not all roses. There could be a few problems with the software's implementation and practical use in the field. Most of them are centred around the age old issue of the software they can account for, but over the hardware that runs it, Google has a lot less control.

If you're using GMN on your Android phone then it's going to tear through the battery, which is massive issue as smartphones get smarter anyway. You'll have to find an adaptor for your 12V car socket or you can kiss goodbye to complete route guidance, let alone a day of actual phone use. This, of course, isn't so much of a problem with a traditional satnav. You're not going to need one of them to make a phone call after you get out of the car.

The very smallest satnavs have got 3-inch displays and many people prefer something around 5 inches for a decent route guider. There's not a lot of phones out there with that kind of pixel power and it's really a tablet that you're going to need to offer that kind of size.

The whole system is going to rely on a decent interface. Google can take care of one end but there's nothing more frustrating than a satnav with a dead touchscreen. This is not the kind of thing that'll make the GMN experience a joy. Pick the wrong phone and you might never use the service again. The same is true of the microphoneto to a lesser extent, but that would only affect the voice control feature.

Now, it might be that Google gets it bang on but TomTom, Navman and co have been practicing with their market for many years. There are touches in their systems like fuel counting and economy settings that don't appear to be part of GMN as it stands. Until we get a good look at the system, we're not going to know what else might have been missed out. Also, as far as commercial organisations go, it's a lot cheaper to buy their drivers PNDs than it is to fork out for Android handsets and educate their employees on how to use them.