I compared the 900 with the 905 when the 905 first came out. Picture wise they were nearly identical on a Sony 11HT projector (a 12-bit 108MHz DAC will make minimal difference compared to a 10-bit 54MHz DAC if the player isn't progressive scan: remember that DVD is an 8-bit 13.5MHz format. A 54MHz DAC samples the entire 13.5MHz signal four times, while a 108MHz DAC samples eight times), but I much preferred the sound quality of the 900.
The 905 reminded me of the 735 and the remote wasn't impressive at all. I ended up with the 900, even given its greater cost. Great machine (I 'upgraded' from an extremely buggy Arcam DV88). Considering the price reduction of the 905, I think the internal audio construction was the area that got the short end of the stick; although to be fair the 900 had been well used and the 905 was fresh out of the box with no burn-in time.
Adam