Should i go slim or stay fat?

[darkserpant]

I have a 40gb ps fatty. I watch a lot of blu's with it. But i was wondering if I were to give my fatty to my son and buy me a slim if it would be a improvement. I dont know what the difference in the slim vs. the fatty in the blu ray watching catagory. I know the one difference if the slim can bitstream and the fatty can't. My reciever is a onkyo txsr805. It is a 1.3 hdmi receiver so I wont have a problem there. So right now my fatty is decoding the the codecs instead of my a/v receiver. But if I get the slim the onkyo will do all the processing. Would I notice a sound difference if the receivere does it instead of the ps3? I posted this question in the ps3 forum but didnt get much response. People there are mostly gamers. You guys are more informative with the blu ray watching. Thanks