One thing I am finding odd, and certainly something some might want to take advantage of, and also a reason why it might be intermittent for some....
The mms I'm sending and receiving (group SMS seem to be counted as mms if you have mms turned on in settings) are not being recorded in the OLAM. It was mentioned by another poster to check and see what number it's being sent to, around page 2 or 3 of this thread, I did and have continued to through out the day, seems to be accurate with about a 3 hour delay, except for the MMS. They do not show up at all, I forwarded several (sms jokes, no multimedia attachments) to groups of people today, none of those are recorded either, just the single sms I sent.
Would also explain AT&T's reticence to turn it on for people. If apple has implemented mms in such a way that AT&T cannot record it at this point in time...they are losing money, in their eyes anyway. I have unlimited data and unlimited messaging so I'm covered, one way or the other, but some might not.