I tried the Easy Downgrader v0.2 around 1pm yesterday and I've gotten success :). My brother's PSP, that has been on 2.80 since that update came out, is now on 1.50 and devhooked. If you feel really confident in what you're doing and have had experience downgrading before, I say give it a shot. The only thing you've got to lose is $250 if you mess it up. And I also updated to 2.00 then downgraded back to 1.50 to get that "clean" firmware.
I may decide to make a TUT vid when I get my friends PSP to downgrade.
Hmm...my brothers firmware history?