Ok so the sound cuts in and out for me, but there seems to be several people experiencing technical issues.  I'm wondering if this is something to be with older PS3s because I find it hard to believe that Sony would release a demo this buggy.  

i have a 60gb and i had no bugs with the demo

I've got a launch 60 gig model, works fine.

I have a 40 gig model.  the sound was OK for the most part but the graphics were very glitchy, with lots of flicker on the main characters.  Also, at just about the end of the demo (leaving the crime scene) the game cut to a black screen, locked up my ps3 (couldn't open the xmb to quit), and I got a blast of white noise that wouldn't stop until i shut off the console.

250 gig slim; no issues.

 No issues on my 60.

both demo and game bugged at times for me..

The demo worked great on my 60 GB model. I didn't notice anything unusual.

day one launch console and no bugs or glitches on 3 demo playthroughs -hope it stays that way for full game

I only had a weird floating cigarette on my 60gb

My demo only crashes if I  play the trailer before playing the demo.

I have a the 80gb PS3 with the software PS2 emu., worked fine for me

Got an old 60GB and it works fine.

my old 60gb never had issues, and I played through the demo several times.

I had the Sliding Lady bug, but it was clearly the game and not the console.

I heard static sound effects while at the top of the hill as the FBI agent.....but also had this weird static noise in the GOW3 demo when the giant (crushes helios in hand) moves around.
 
60 GB PS3 with latest firmware.