I've used a number of Samsung Android devices in the last few years; five if we include my Nexus S and Nexus 10. I've watched their big screen flagship models evolve from the S II, S III, S4 and the S5, ignoring the Note line. The current "everyday" Samsung flagship is the Samsung Galaxy S5, announced in February this year. The S5 is based around a 5.1-inch, 1080p SuperAMOLED screen, a 2.5 GHz quad core Qualcomm Snapdragon 801 processor and 2 GB of RAM, backed up by either 16 GB or 32 GB of internal storage together with a MicroSD card slot. It runs Android 4.4 Kit Kat under the TouchWiz interface. The rear facing camera is 16 MP and is joined by a heart rate sensor. Things are kept alive by a replaceable 2,800 mAh battery. The S5, however, features IP67 water and dust resistant certification, meaning that the device is essentially "life proof," that is, you can take it anywhere without worrying too much about damaging it through liquid or dust.
Towards the end of the year and looking back at the S5, in particular the specification, I'd say that it's still contemporary apart from the screen resolution, which is "only" 1080p so that means it's 1,920 by 1,080 pixel resolution. Some other flagship handsets, such as LG G3 and the Google Nexus 6 have (admittedly larger) displays with more pixels at the "QHD" level, or 2,560 by 1,440 pixel resolution. More is usually considered better but at the sorts of distances that I use my smartphone, I see limited difference in sharpness going from 720p to 1080p or QHD. I do, however, appreciate stronger color saturation and subtle brightness controls; I like my screen dim at night and bright when I'm outside. It seems that Samsung are of the same opinion as they have refreshed the S5 with the new Samsung Galaxy S5 Plus with a very minor specification polish. The old Snapdragon 801 processor is out and replaced with the newer Snapdragon 805, again still a 2.5 GHz, 32-bit, quad core unit. The old standard LTE network is out and replaced with a higher speed component. Everything else is pretty much the same, which begs the question: why did Samsung replace the 801 with the 805?
Looking at the Snapdragon 805 compared with the 801, the key differences are that it can be clocked at a higher speed, up to 2.7 GHz. That's not relevant as Samsung have clocked it at 2.5 GHz. It does, however, feature a new GPU, the Adreno 420, which replaces the Adreno 330. The new GPU is significantly more powerful than the outgoing unit; in Anandtech's independent testing, they discovered that the Adreno 420 is as quick driving a QHD resolution benchmark as 330 at 1080p. The QHD display has 78% more pixels than the 1080p display... the S5 Plus is going to be capable of delivering very fast video performance. Also, the 805 has much, much higher memory bandwidth compared with the 801; it's around twice as quick at shunting data around. Qualcomm boosted the Snapdragon 805's imagery and camera technology as it can support a 55 MP camera compared with 21 MP for the 801 (not relevant; the S5 and S5 Plus have a 16 MP camera). There's some power management improvement functionality in the 805 compared with the 801, too. I'll add a note that the higher performance LTE radio is handy if your carrier supports it; it can download data at up to 225 Mbps.
In short, what we have here is a polished Galaxy S5 likely held back by the hardware or your carrier. I don't expect there to be any noticeable differences in the hand between the two devices and this is reflected by the price; Samsung Netherlands have confirmed that the Galaxy S5 will be out later this month at a price of â‚¬599 for the 16 GB model. This is about â‚¬100 more than the regular S5. My advice: unless you need the higher performance LTE Advanced network, save your â‚¬100 and go for the standard S5. Or wait a few months for a 64-bit S6 next year.