Motorola introduced the first Moto G back in 2013 and it was a delightful device, delivering impressive specs for a low price and consequently causing upheaval in the budget handset world.

Since that 4.5-inch original (2013, first-gen), we have seen a 4G model of it (2014), a larger version minus 4G (2014, introducing the second-gen), followed by a similar larger version with the addition of 4G (2015). That gets you up to speed with the Moto G story taking us to where we are now - the launch of the fifth handset and what is being called the third-generation design release of the Moto G.

With just three short months since the last Moto G launch there's potential for confusion. So we have crunched the numbers and compared the specs to help you work out what's changed in the new Moto G 2015 and what the differences are between it and April's release.

The second-gen Moto G 2015 measures 141.5 x 70.7mm and features a curve between 6 and 11mm. It hits the scales at 155g, which isn't light, but it is somewhat alleviated by the curved, smooth back with its soft, warm-to-touch matte finish that the Moto G is known for. It has a bulky design with silver bars running across the front that we weren't overly sold on compared to the original 2013 model.

In terms of finishes it comes available with a black base colour only but Motorola does offer what it calls Shells and Flip Shells in order to bring some life and colour to the device.

The third-gen Moto G 2015 measures 142.1 x 72.4mm and features a curve between 6.1mm and 11.6mm. So the newer model is slightly thicker and bulkier the previous model, albeit less tall. It still weighs 155g, though, meaning it's the very same weight despite the design tweaks.

The silver bars on the front have taken a back seat, much to our liking, and the rear sees the camera lens and signature M indent are made into more of a feature. The new model is also IPX7 water-resistant which is great news for the G range.

Perhaps more excitingly, however, Motorola is not only offering the black or white rear colours, like it did with previous models, but the new Moto G will be available through Moto Maker.

This means that users will be able to personalise their third-gen purchase a little more, like they can with the Moto X and Moto 360. The rear panel of the new Moto G 2015 will be available in cherry, cabernet, blue, raspberry, turquoise, black, gold yellow, white, lime, or navy. Accents colours include metallic versions of blue, red, lemon lime, champagne, black, orange, violet, pink, dark chrome or light chrome.

There are no wood options, like with the new Moto X Style, but the third-gen Moto G can be engraved and offers Shell case options (just like the second-gen model).

The Moto G 4G 2015 model comes with a 5-inch 1280 x 720 pixel resolution IPS display, delivering a pixel density of 294ppi. It's not the sharpest display out there, given that the majority are Full HD and above, but this device is £149 so that needs to be considered.

We felt the viewing angles were strong, colours were vibrant and the brightness was more than ample to resist excessive reflections when we reviewed it. Unlike some more budget options, there's an adaptive brightness setting on the Moto G so the phone can adjust for ambient lighting conditions.

The new Moto G sticks with the same 5-inch display size and the same resolution at 1280 x 720, meaning you'll get a very similar experience to the model launched three months ago. With a bump in resolution to Full HD, the pixel density would have crept up to 440ppi, which is a big difference over the previous model, but sadly that was not to be this time.

The second-gen Moto G features an 8-megapixel rear camera with an f/2.0 aperture lens. There is 4x digital zoom on board, the option to tap anywhere to capture, and an LED flash. It also offers features such as burst mode, slo-mo video and autofocus. The front camera is 2-megapixels.

We found the rear camera handled well for this price point when we reviewed it and daylight shots worked well. Low-light shots weren't as impressive but this is generally the case with many smartphone cameras.

The new Moto G looks to steps things up quite a lot in terms of camera performance though, especially when it comes to the amount of megapixels. There is a 13-megapixel snapper on the rear with dual flash, coupled with a 5-megapixel snapper on the front. Many of the other features are the same as the second-gen model - so if you are used to the Moto G camera, you won't need to learn new ropes, and if you aren't then it's simple to navigate.

The second-gen Moto G comes with a 1.2Ghz quad-core Qualcomm Snapdragon 400 processor paired with 1GB RAM and Adreno 305 GPU. There is just 8GB of internal storage but there is microSD support for further storage expansion, although this means the dual-SIM functionality becomes redundant.

The third-gen Moto G arrives with the 64-bit 1.4GHz Snapdragon 410 processor, 1GB RAM and 8GB of storage. There is also a 16GB version available that will offer 2GB of RAM (adding £30 extra in Moto Maker). Both new Moto G 2015 models have microSD support.

In terms of battery capacity the second-gen Moto G has a 2390mAh capacity, while the new Moto G offers a slightly higher 2470mAh capacity. That should translate to a slight bump in life increase per charge, but not necessarily a drastic one in light of the change in processor.

One of the great things about Motorola is that it offers a very close to raw Android experience when it comes down to the software. There are only a few Motorola-specific apps that have been added on top so you get a very clean experience.

The second-gen Moto G runs on Android Lollipop and gets regular updates to the latest versions. The third-gen Moto G will also run on the latest version of the Android system, but it will add Motorola's new Messages app, as well as the Moto app (which allows you to use voice commands and more).

Eventually the second-gen Moto G will get this update, however, so the user experience will be the same as the new Moto G.

The new Moto G, or third-generation Moto G as it's referred to, is a moderate shake-up to the series. The storage and RAM capabilities have also been increased, which will help with the overall performance and you'll also get the latest software too.

But there are three main take-away points from the new model: water-resistance, the option for Moto Maker customisation, and a better camera on board.

However there has been yet another bump in price, from the £149 of the second-gen model to £159 for the third-gen. Moto Maker options begin from £179. That gets higher still with additional customisation, while the 16GB model starts from £209. The original Moto G started at £135 so it has slowly been creeping up in price since its initial launch.

Although the second-gen Moto G is powerful enough, for the sake of an extra tenner for the entry third-gen model, we reckon the new Moto G 2015 is well worth it. It's still a lot of phone for under around the £150-£180 mark.