Been running the pure Google Edition ROM on my T-Mobile Galaxy S4 for a couple hours now.
Gotta tell you guys something, the S4 DEFINITELY needs this ROM. It transformed it into an actually usable device now, no more constant micro-stuttering and lag (Which made me want to throw it out the window every time I use it). Unfortunately on the S4, Wifi doesn't work. The S4 performs much better without all those useless Samsung crap.
On the other hand, In my opinion the HTC One is near perfection out of the box already. (Even better with the leaked 4.2.2 Sense ROM) There is zero lag in the UI, Sense 5 seems very lightweight and it has a bunch of awesome features that I use everyday. For example the music player is GREAT, it has scrolling lyrics. I tried to find a good music player like the HTC one for the S4 but to no avail. I can't give that up. The Camera options are another that I can't give up, I love that it compiles all your videos and pictures into a cool professional looking 30 second "cliff note" video of the day, my wife and kids love that. Great feature! IR remote control, can't live without it and with the Google edition it's gone. Last the not least, the Browser. I love the HTC browser, it is buttery smooth, has native flash support, auto fit, performs flawless. I can't give that up for Chrome which is the browser that comes with the Google firmware.
Chrome is nice but it doesn't support flash and the performance is subpar. For example scrolling is not smooth, a little jittery. It seems like it scrolls at 15 frames per second, and the stock native browser is smooth at 60 frames per second. Same thing on the S4 with the included Chrome browser in the Google firmware.
Take my opinion with a grain of salt, if you have Galaxy S4 with S-Lag, you definitely need this ROM. I would gladly give up all those gimmicky features in TW for a smooth UI experience any day. With the HTC One, the UI is buttery from the start, and all those goodies that HTC threw in are actually positive perks.
My S4 will be running the Google ROM, and my HTC will stay with Sense.