Ahh suddenly become Samsung vs Sony. Let me chip in my 2 cents

I've used Ericsson 768, SE T630, SE X10i, SE Xperia TX, SE Xperia ZL. I've always liked Sony's design, and I believe they produce the sexiest phones in the world. But somehow I feel as though Sony software does not take advantage of the hardware. Like the X10i, the hardware was top notch at that time, but the buggy and laggy software really let it down. Even now, with ZL in my hands, it doesn't feel like this year's tech. Fully factory reset, the homescreen feels laggy, and the animation where the app launches feels like it's skipping frames.
In contrast, Samsung phones are plasticky, and the design is... just passable. But they are the most lenient in warranty checks, and remain popular with the 2nd-hand market. Hacker-friendly and easy to return to stock, with plenty of dev support. Some say the S3 hangs, lags, heats up, etc, but from my few months of use, I haven't had any of those. Even stock is good enough, which is surprising to me (never mind the bloatware, we can just disable those, which is just as good as removing them). Stock launcher is smooth (although not functionally enough for me, I prefer MiHome or Nova), even smoother when compared to a fresh reset ZL or Butterfly.
Of course, I'm still very much interested in Sony phones, otherwise I wouldn't be holding a ZL now.