Unpopular opinion below.
I've owned an L920, 925, 520, a Samsung Focus, and currently am on an ATIV S Neo, and I have to say that the Neo has offered the best WP experience over my entire career. All my Lumia's suffered heating issues (especially the 920 and 25, I got several replacements for the former) as well as a few other issues in build quality. The Neo never really got beyond uncomfortably hot, Samsung is pushing out app updates at a reasonable pace, the camera is actually quite nice for my standards, the screen is beautiful, and the expandable storage and removable battery just takes the cake.
The real nice aspect was that doing resource heavy tasks never heated up the phone enormously, whereas some basic tasks on the Lumias heated them up a lot, though I suspect the 925 with its metal perimeter helped facilitate the heat; whereas Samsusng's build material is not completely conducive for heat. However, the plastic/polycarbonate casings for the 920 and 520 still got REALLY hot. I personally don't think Nokia has mastered heat dispersion adequately, but that's just a personal opinion. Other than a few more gripes I've had with Nokia's phones which I can't remember right now because I'm feeling a bit ill, I think Samsung sometimes makes a better windows phone and they're not even trying.
Sorry for the run-on sentences, as I'm not feeling well.