Nothing wrong with the current PS3 slim, and I upgraded my PS3 hard drive with a 1TB samsung spinpoint m8 2.5" 5200rpm 9.5mm (can't be any thicker that that size)
Was a great buy for £70.
The top loading thing has it's good and bad points.
Same as what the PS2 slim had, which made it more flimsy.
But if the disc ever gets jammed inside the old type they have to be sent to repair and the disc inside could be lost or scratched.
However being super slim and having so much processor power, I suspect they would have cut corners somewhere and probably won't have decent cooling.
But will see when it's released as people with TONS of money they usually take apart a console,etc and see whats in it on youtube to determine how good or bad it really is made.