Monticello is quite good, especially with Metacello associated to it. I'd like to have the MetacelloToolBox working nicely with FTP repos and will spend a while on that in the coming weeks, but frankly, that's great to use to keep things in sync.
I'd pay for STH but for private projects and with the bells and whistles of GitHub (Wiki, issues, teams, non smalltalk files etc).Long story short, GitHub is good also. Maybe consortium members fees could get into have STH supported. Phil