Plenty of other people have pointed out that the Blarite think-tank-cum-pressure-group Progress hardly deserves to be compared with the Militant Tendency: it isn't a party within the Labour Party, which Militant was, and there are no grounds for proscribing it. Yes, it has an ideological agenda, yes it is bankrolled by a millionaire -- but then so was Tribune for much of its early life (in fact, there were at least three millionaires who kept it going).
What no one has said so far is that, for all its cash, Progress has been singularly useless at setting the political agenda. It's certainly a networking opportunity for the Labour right -- but in more than 15 years of existence it has produced almost nothing worth reading. Tribune and the Fabian Society might be going through hard times right now, but both have an intellectual confidence that puts Progress to shame, as indeed do Compass, the Labour soft-left think-tank-cum-pressure-group, and Policy Network, a European right-wing social democrat think-tank-cum-pressure-group. "Feeble group attacked by feeble union boss" isn't front-page stuff, but it's the truth.
And finally, I know it's off on a tangent, but I'm reminded of an old adage from the 1980s that was commonplace among anarchists, communists and the Labour soft left. "Rule number one: no bans or proscriptions! Rule number two: no Trots!"