Here's my review of .901:
Living in a 4G fringe area, .886 was pretty good after I replaced my SIM card, but I still got occasional drops where I had to reboot / airplane toggle. I rate the phone at about 75% of data connectivity. Update .893 update made things exponentially worse for me, transitions required me to actually reboot (restart connections or airplane mode didn't restore connection like they did on .886), multiple times a day. I rate the phone at about 40% of data connectivity.
I've noticed a huge difference being on .901 so far. On .901, 3G to 4G transitions happen really quickly and have been flawless. 4G signal seems to be holding much stronger, and I have 4G and 3G connection in areas of the house i didn't before. Still have some dead spots in the house where I get no connectivity (seems like more of a network not a phone issue), but it'll transition from no connection to 3G - 4G quickly as soon as I move to an area of the house that gets signal.
I haven't had to reboot / airplane toggle once since the .901 update! I rate the phone at about 95% data connectivity now. I think the remaining 5% is probably just network issues / certain parts of the house causing poor signal transmission. For me, it's a vast improvement over .893 which was a total failure of an update for people in 4G fringe zones.