Sony announced a new mid-range smartphone at Mobile World Congress in Barcelona rather than a new flagship, but just because the Xperia M4 Aqua doesn't have a 'Z' in its name, it doesn't mean it should be ignored.

The Japanse company has gone to town with the Xperia M4 Aqua, delivering waterproofing, a decent number of megapixels for both cameras and a hefty battery life, all within a very similar design to the flagship Xperia Z3.

So how do the two devices compare? We have put their specs up against each other to see what the differences are from mid-range and flagship and whether the Xperia M4 Aqua has enough in its favour for it to be considered a feasible flagship alternative.

The Sony Xperia M4 Aqua measures 145.5 x 72.6 x 7.3mm, while the Sony Xperia Z3 measures 146 x 72 x 7.3mm so in terms of physical size, the two handsets are almost identical. The Xperia M4 Aqua is slightly wider but the Xperia Z3 is slightly taller and the difference is so minuet you wouldn't notice.

There is a big difference in weight however, with the Xperia M4 Aqua coming in at 136g compared to the 152g of the Xperia Z3 and when holding them at the same time, it is noticeable how much lighter the mid-ranger is.

Numbers aside however, the Xperia M4 Aqua and the Xperia Z3 feature the same look. Both have the OmniBalance design with the curved edges and flat slab front and backs, while the corners are rubberised to help if you drop either device. They are also both IP65 and IP68 waterproof and dust resistant.

There isn't much to differentiate the two devices in terms of design, but the Xperia M4 Aqua does have an open Micro-USB charging port, while the Xperia Z3's is covered by a flap. This means the new device doesn't have the two-pin dock connector either so the overall design is a little cleaner than the Xperia Z3.

In terms of colours, the Xperia M4 Aqua comes in black, white, coral and silver options, while the Xperia Z3 is available in black, white, silver green and copper, as well as purple.

The display is the area the Xperia M4 Aqua falls well under the Xperia Z3. Mid-range devices have to sacrifice some elements to keep the costs down and the display is normally one of the first places to take a hit. The Xperia M4 Aqua has a 5-inch display, which is only 0.2-inches smaller than the Xperia Z3's but it is the resolution where the difference in the two is apparent.

The Xperia M4 Aqua has a 1280 x 720 pixel resolution compared to the 1920 x 1080 pixel resolution on the Xperia Z3, resulting in a pixel density of 294ppi compared to 424ppi, respectively. This means the Xperia Z3 has a much sharper, crisper display than the Xperia M4 Aqua as more pixels are packed in per inch, delivering more detail.

When we had the Xperia M4 Aqua and the Xperia Z3 side-by-side we did notice a difference between the two handsets, with the mid-range device showing more fuzziness at the top than the Xperia Z3, but this was what we expected so we weren't too disappointed. Both offer lovely, bright and vibrant colours so the Xperia M4 Aqua doesn't fail completely, but the Xperia Z3 is better in terms of display.

The Xperia Z1, Z2 and Z3 were all heavily marketed on their camera, with all three boasting a 20.7-megapixel snapper on the rear. The Xperia M4 Aqua reduces the resolution slightly at 13-megapixels and takes the ISO sensitivity down from a 12800 maximum to a 3200 maximum, so the flagship wins that battle in terms of numbers.

It's worth remembering that 13-megapixels is above average for a mid-range device though and the Xperia M4 Aqua will come with the same suite of camera apps found on the Xperia Z3, including Superior Auto that automatically adjusts the camera settings for the best shot and Sound Photo that allows you to add short slips to your images.

When it comes to the front-facing snapper, the Xperia M4 Aqua is surprisingly the device that comes out on top. The mid-ranger has a 5-megapixel front camera over the Xperia Z3's 2.2-megapixel and Sony has said the Xperia Z3's software features will be available on the front-facing camera too, which they previously they haven't been.

The Xperia M4 Aqua comes with a 1.7GHz quad-core Qualcomm Snapdragon 615 processor and Adreno 405 graphics, while the Xperia Z3 has a 2.5GHz quad-core Qualcomm Snapdragon 805 chip and an Adreno 330 GPU under its hood. This means the flagship will be a little better at handling the more complex tasks, especially given its 3GB of RAM support. We weren't told the Xperia M4 Aqua's RAM but we suspect it will be 2GB, if not 1GB.

When it comes to storage, the Xperia M4 Aqua has 8GB internal memory, while the Xperia Z3 comes with 16GB. Both are expandable via microSD but the Xperia Z3 can support memory cards up to 128GB, whereas the Xperia M4 Aqua is likely to be less, probably up to 32GB or 64GB.

Battery life is claimed to be two days for the Xperia M4 Aqua and its 2400mAh capacity, which would be pretty good going if this claim turns out to be on point. The Xperia Z3 has a 3100mAh battery, which Sony also was claimed would deliver a two-day life when it launched. Chances are the Xperia M4 Aqua and the Xperia Z3 will sit pretty close when it comes to battery despite offering different capacities however, as the Xperia Z3 has a slightly bigger and higher resolution display to power with the extra capacity. 

The Xperia M4 Aqua will launch with the latest and greatest from Google - Android 5.0 Lollipop, while the Xperia Z3 is currently still waiting for the upgrade. It will get it eventually though so you'll get near enough the same software experience with both devices.

Sony's overlay will be on top of Android, so services such as Sony Entertainment, Xperia Lounge and Sony Music will all be easily accessible on both the Xperia M4 Aqua and the Xperia Z3.

One thing you won't get with the Xperia M4 Aqua however, is the Remote Play feature that allows PlayStation 4 users to play games from their console remotely. This feature was launched on the Xperia Z3 flagship back in September 2014 and while Sony said it would back date to some of the older Xperia devices, it won't be coming to the Xperia M4 Aqua.

Sony has said the Xperia M4 Aqua will cost €299, which directly converted is around £237. We suspect the final UK price will be slightly higher than the direct conversion though, maybe somewhere between £250 and £270. 

The Xperia Z3 on the other hand, will set you back £549 so while it may be cheaper than other flagships, it is still likely to be at least £250 more expensive than the Xperia M4 Aqua.

Even if you opt for the slightly smaller Xperia Z3 Compact with its 4.6-inch display, you are still looking at over £400 so the Xperia M4 Aqua doesn't shape up too badly if you are willing to take a slight hit in specs.

The Xperia M4 Aqua may not win every number comparison contest when it is put up against the Xperia Z3, but it certainly provides some food for thought.

The two handsets are pretty much equal in terms of size and design, but the Xperia M4 Aqua is lighter, has a better front-camera with software to add some fun to your photos, and it runs on the latest Android from launch. 

The rear camera of the Xperia Z3 may be better, and the flagship comes with a faster processor, more storage, a sharper, bigger display, plus Remote Play. Both quote a two-day battery life though and with a £250 price difference, the Xperia M4 Aqua is certainly not a device that should be ignored. 

READ: Sony Xperia M4 Aqua hands-on