The way I see it
For pilots approaching retirement (50ish+) who want to stay on - by all means sign up to CoS08 IF YOU ARE HAPPY WITH THAT DEAL.
For those of us not in that position, stay on CoS99. You will keep your existing conditions and entitlements, and Bypass pay will happen faster (due to all categories of pilots extending, not just C&T's).
It seems that we get a new iteration of CoS about every 5 years. If that is the case, by the time most of us come up to age 55, there should be a new CoS anyway - and I'll bet my leftie that age 65 retirement will form part of all future CoS change proposals. Anyone that believes that "this is a one time offer" needs their head read. That line was just put in to scare the borderline people into taking the new contract NOW. It also seems that it will eventually become Government legislation - again a win (per se), as you will be able to keep CoS99 to age 65! Easy decision for me to not sign up to CoS08.
SLS - I will be considering taking it based on what I believe is a well informed AOA GC recommendation. However, I will not take it until the last minute, after all negotiations and debate is finished.