I, too, ended up not having a choice about accepting the update. I had my phone on my nightstand while I was watching tv with my wife. Went to bed and saw the update message, with about 30 seconds to decide to defer or hit okay before it installed. While I was debating and seeing if I could pull up the update description on my Xoom, the install started.
I haven't noticed any issues, but also no improvements yet. Tomorrow I can try S Beam again; when my brother-in-law tried it with his S3 and mine, it wouldn't work. Maybe the update fixed whatever was going on so it'll now work. (Not that it's a big deal anyway, since he and his wife are the only ones I can use it with, lol.)