Is the Onkyo 705 worth $250 more than the 605 for 7.1 Matrixing only?

[krizzz]

Sorry for the double post but I didn't notice a "Receiver" forum earlier...

Hey all - I am in the market for a 7.1 HDMI receiver to mate with my PS3. I am torn between the Onkyo 605 and 705. I'm not concerned with the additional inputs or the THX2 certification.

The only factor leading me towards the 705 at ($250 more) is that it will matrix 5.1 into a 7.1 sound-field. I figure that if I am going the 7.1 route, it would be nice to have those speakers popping for every movie.

So my questions are these:

1. Does anyone have the 705/805 and use the matrix on 5.1 signals?

2. Does it improve the movie experience or just sound hokie?

3. Does it only work with certain audio outputs (eg only PCM, or only bistream, etc.) If so, would I be using an inferior quality audio track to enable the Matrix effect?

Sorry if these are dumb questions, but the new audio formats are still a bit confusing to me.

TIA.