Just a thought from my side: I do like ProgressTalk.com better than the PEG. Although it seems that the discussions on PEG are much more lively I don't like the email as communication vehicle at all. In the end it's not possible for me to participate on the PEG via email from my working equipment and I don't see any point in carrying more than one laptop with me just to be able to. Furthermore I like the forum philosophy better, although it might be more vulnerable for SPAM.
But that is - of course - IMHO.
Heavy Regards, RealHeavyDude.