I want 3.7 or maybe it's 3.8. I forget. Whichever one gets me 3d movie blu-ray playback with DTS Master Audio high definition audio playback. 3.5 gets 3d playback, but not with high def sound at the same time. Irritating. Thinking about just upgrading to OFW as there are some recent games I want to play as well and GT5 update came out recently with interior views and such that needs at least 3.6.
Convenience factor of not needing to swap discs in and out and just staying on my couch and loading a different backup is nice, but if after I finish a couple more games I have on my stack they haven't got this figured out I'll probably update to 3.7 or 3.8 or whatever, but not all the way to 4.0 as 4.0 doesn't appear to have anything I want.