I am looking at getting a ps3 slim and lobbing on CFW... I know that right now I would need to ensure the system comes with no newer than 3.55, and I wont be able to play most new games on it due to the 3.6 issues.
With the iminent new FW coming out with the relaunch of PSN, there is surely going to be more security rolled in... as no-one has yet been able to make a CFW of 3.6, should we be concerned that the good days are coming to an end, or are you hopeful of a 3.7 (or whatever they call it) CFW coming out in the near future?
Some shops have old stock! But you can ask the seller what version is on the console. if you don't want to play online the Kmeaw 3.55 it's perfect! No release date for new costum firmware with psn support. Cheers!