I installed the Sept update on my 75" 900F, and after some time with it I can report I definitely do not have the issues reported above and I'd know it if I did as it's a workhorse primary HT and PC monitor.. I do notice the TV's menus are much crisper now, the previous sluggishness is almost completely gone.
What may be entirely in my head and I'm wondering if anyone else sees this, is that it appears to be making the black bars during film content a bit darker than before. One of my few disappointments with what is otherwise a great set is that the black bars aren't as black as they are on my previous Sony FALD or my friend's Vizio FALD, and it can't be adjusted to those sets' level of darkness even when the picture is adjusted to be unreasonably dark. I've tested it on my normal settings with movies in Netflix and also letterboxed SNES emulator games on the PC and in both cases it seems to be better now, not ideal, but acceptable given the other PQ advantages this set has over the previous two I mentioned.