How is the Blu Ray player and DVD upconvenrting audio/video quality and load times compared to other dedicated Blu Ray players?
I have a PS3 Slim.
The DVD upconverting is considered mediocre. Casual viewers can't tell the difference. It might make a difference if you have a HUGE screen. For example, if you have a 100" projection or something, you'd probably want a better upscaler. It is perfectly fine for normal range of TVs up to 60" or so.
The BD quality is top notch for video and audio. Load times are very fast. It supports 3D. It gets frequent updates and as such is compatible with many BD titles that are troublesome on other players.
The PS3 has a long history of both gaining and losing features. Features gained include newer BD revision support, newer HD audio formats support, frequent title and bug fixes, video streaming (Netflix), and 3D Blu-ray support. Features lost include half the USB ports, media slots, hardware PS2 compatibility, software PS2 compatibility, SACD support, and OtherOS support.
The PS3 is region locked and won't play 50Hz content, so be very careful if you import movies. This is not a problem if you stick to buying titles in your region.
The Slim is quiet enough for home theater use. I've heard some people say the Fat's fans are too loud, but others say it's fine. I have no experience with the Fat.
The Slim can bitstream all of the lossless HD audio codecs. The Fat cannot bitstream those, but can decode them and output PCM.
My main complaint for home theater use is the lack of an IR port. Because of this, the situation for using a universal remote control is expensive and somewhat awkward.
The shape of the chassis isn't really suitable for stacking with other standard home theater equipment. (The PS3 has to be on top.)
If you are a gamer, it's a pretty good deal. If you're not, it's a bit expensive and awkward. Another contender for top blu-ray player is the Oppo. You might want to look into them if you aren't a gamer.
I hope this gives you more reasonable information than those people who say nothing more than "the PS3 is the BEST EVAR!!!1!!!1!!"