I have used both debranded firmware on a GoPhone and the Postpaid AT&T 635 with the AT&T firmware. I can tell you that it does "seem" faster in day to day use, but as an actual test, a soft reset takes about 1 minute 10 seconds with the AT&T firmware, and less than 30 seconds with the unbranded country variant firmware. This is on the same phone, with the same apps installed except for what AT&T installs. Even after uninstalling the AT&T bloatware to give the same list of installed apps, it has a soft reset time on the country variant that is definitely faster.
I can't guarantee it will be the same way for everyone, but that's my real world tests. I did multiple flashes on the same phone for the purpose of testing just this so that I could make a final decision on which way I wanted to go. I had the time (being retired), so I took the time to play around and see.
Other than the "soft reset" being faster, I can't give any real world proof of day to day being faster. It just "seems" that way to me. Could be placebo. I'm tempted to purchase a new back cover shell without the AT&T logo and see if the placebo makes it even faster still. ;)
07-07-2015 01:16 PM