I have an Onkyo 805, just set it up yesterday. I also have a 60GB PS3 as a Blu-ray player. I have close to 30 Blu-ray movies, and not one game.
I did not want another Sony product.
I did not want a game machine.
I did not want a player that wasn't shaped like a box (blend in my AV rack better).
Then I learned that the PS3 loads movies faster than most if not all other players.
It has an ethernet port, which makes updates a breeze.
It seems to be the most stable player, and has no problems with BD-java or extras such as Liar's Dice (that don't work properly on some players).
It will almost certainly get a firmware update to support 1.1, and probably passing the bitstreams (rather than decoding them internally).
It gets regular firmware updates and will certainly be around and supported for many, many years to come.
It serves as a media center to show pictures, etc - and accesses my other PCs on the network to show stuff from them, too!
I can easily download movie (& game

) previews for free.
It has a (currently crude) internet browser built in.
I can load another OS (Linux) on it if I want, and could run programs or use another browser.
More home media center functions are coming.
And it was the cheapest Blu-ray player available!
And it actually looks pretty good on it's side in my rack.
Drawbacks? Well, a dedicated player
may be easier to use. Right now, I turn it on, and slide a Blu-ray movie in, and it starts right up. But if I want to do a firmware update, I have to go thru a menu. Not a terribly complex menu, but one with a lot of options that don't apply to me, as I am not a gamer. Minor, to say the least. And the thing doesn't use IR for remote control, so I can't use my Harmony unless I buy an aftermarket "translator."
I figure one day when dedicated players get better and cheaper I'll get one, and move this to my bedroom - or sell it. As a game machine, it should keep more value over the years so I'll get some return on my money.
If you do get a PS3, get the remote.