Aside from the highly irritating phantom tap issue, the 1520.3 is pretty much incredible.
Playing around on the wife's 920 and mother in law's 520, I almost feel that the phantom taps on my 1520 are on par with the other devices, no worse. Either they made alot of progress with software updates (im on 8.1.1 DP w/ Cyan) or this problem is present on the other two devices as well.
The 1520 is hands down the best phone I have ever owned. I wish some of the software tweaks availible on other flagships (like a better audio eq and processing tweaks, one handed layout of keyboard, split screen for two apps, ability of keyboard to remember email address login so you can just paste it in, and things like that) and im really high on the ir blaster for my phone being my remote control, some say gimmick, I say its almost a must have
But the over all creature comforts the Lumia 1520 has are too many to really ever think of leaving the Lumia family for something like the HTC m8. Things like the sunlight readability mode, placement of the power button, dedicated camera button, glance screen, double tap to wake (though other OEMs are offering that tech now), polarized screen layer to reduce glare, super sensitive touch mode, ect.
I used to want every new phone that came out, since the 1520 (other than the IR blaster) I have not wanted any other phone regardless of the latest and greatest and I was a junkie ask my wife, she hated how I was never satisfied.
You made a great choice and I hope ypu enjoy your 1520 as much as I do. I am a little envious that ypu are getting the 1520.3, that being the only phone that os better than mine
Sorry for the long post