While I've only been playing with installing phpgroupware, I do have to say the one reason I've been playing around with it is because the current WebMail solution just doesn't meet my groups needs. I've currently got a support group using the new-ticket module, and they want a way to 1) have a mail role account (support address) that they can all check, respond to. 2) They want to have e-mail <-> ticket integration. So that they can reply to a ticket, and the user can just e-mail a response and it will go into the ticket db. On another vein, I will soon have time to start working on the Intranet module again, and start fixing some annoying bugs.
My 2 cents..