A year on and Samsung has another flagship ready in the form of the Samsung Galaxy S5. Time to upgrade? Quite possibly.In terms of look and feel, the S5 is a little larger and (bucking a trend) a little thicker too. It's also heavier as a result (145g compared to 130g). That isn't down to the build, which is largely similar to the S4 with a plastic rear casing. But there is now water resistance to one metre and rustproofing too. Talking of size, the screen doesn't get much bigger either. It's now a 5.1-inch Super AMOLED display with 1920 x 1080 resolution, so just a touch bigger. Nothing you would notice.That's not the case with the camera. Samsung has opted for a 16-megapixel sensor that can shoot 4K video, throwing in some tasty additions of real time HDR and background refocus. You'll also find a 2.1-megapixel camera on the front for those selfies and networking, which is a strength too. All of that certainly puts the 13-megapixel camera on the S4 in the shade.The processor has also been boosted, with the new 2.5GHz quad-core Snapdragon 801 processor to be found in the S5, as opposed to a 1.9GHz quad-core Qualcomm Snapdragon 600 processor in the S4. Speed will not be a problem. Then again, it wasn't really a problem in the S4. You just get more of it.So overall, a step up the ladder for most features. But Samsung loves a killer feature and in this case, it has one with its sensors. A fingerprint sensor is housed where you would expect to find the home button. A swipe of the phone opens it up, with the added bonus of being able to buy securely via Paypal using that same fingerprint. It makes a lot of sense.On top of that, the sensors are also present for one of the big mobile battlefields of 2014, health. A sensor is present where your index finger usually rests in 'hold'. That works in conjunction with the S Health 3.0 app within to keep a track of your wellbeing during the day. If you are a hypochondriac, that might add to your stress every time you access your phone. If you just have a more balanced interest in your health, it's an interesting addition.That's the thing here. The sensors are the killer feature, but it perhaps depends on whether you buy a lot of things via your phone (using PayPal) and your interest in your health. Everything else has been given an upgrade and of course, there's always the bragging rights of having something new.But ultimately it will come down how much value you put on those new features. The S4 should be available cheaper next month, as the S5 takes the premium slot. It might not be a bad option if you aren't obsessed with health.