WOW. Really wanted to thank folks for taking the time to chime in. So much great feedback and while I can read a dozen reviews of which half the material is over my head, this real life feedback, for what is worth, means a lot.
Based on what I am hearing the 2.8 IS might hurt me more than help me hand with AF.
Really brings be down to 70-200 F4L IS versus 70-300 F4-5.6L IS (and yes I was thinking the L to one of the posters, not the non L version) and the more I hear the feedback on the 300 being sharper at the extreme ends, then it sounds like for my portrait work, below 100 it is either sharper or the same, I may give up a little bit in the middle, but as I get closer to 200 and beyond, I start getting the advantage back.
Pulled the trigger on a 24-105 F4L today on a RytherCamera Cyber Monday sale. $899 real hard to pass up, though have heard some customer service nightmares, mainly Bait and Switch... So at least AMEX has been good to me resolving issues, so think I am o.k. Won't sell my 18-135 just yet, but with my hood, should bring my cost on the 24-105 down to $700 or so.
Difference is $230 between the 70-200 F4L IS and the 70-300 F4-5.6L IS is really not that much for an extra 100m worth of range with similar performance and on my T2i or 7D if I go that route, that is actually 160m more.
Not perfect but I think gives me better balance, extended range and only one lens to replace should I go FF in the future
Thanks again for the great feedback