I'll give a cautious yes
I'll give a cautious yes, because on top of reducing the size of the unit by about 33%, the PS3 Slim also reduced power consumption by about as much.
So if you don't care about the PS2 back compat, which might have been completely disabled by a recent firmware update anyway, then I'd say do it. You'll gradually make back that money in reduced utility bills. It might take you another 4-5 years to make it all back and then some, but you're also doing your part to reduce the load on the local electrical grid, being a good citizen.
If you want the PS2 back compat, then don't even think about it. Take the position that they will pry that unit out of your cold dead fingers. I am assuming recent firmware updates didn't kill it off even on the ones with the PS2 EmotionEngine CPU in it.