I've had my wii since January of 2007 and I love it. I decided to get a PS3 a few days ago simply because it's a good price for a blu-ray player.
I have to say, the 40 gig hard drive and downloadable demos are awesome.
Here are pro's and cons as i see it.
Pros of PS3:
downloadable playable game demos
downloadable movie previews
the most amazing video game graphics i've ever seen
Con's of PS3:
After playing the wii for a year I'm finding it really hard to use an old style controller. The wii is soo much better in terms of how you control a first person shooter.
I rented devil may cry 4...it took it 25 minutes to "install" the game before I could play
All in all I think having both is a great combination..now I get amazing graphics when i want to on the PS3 and I get the awesome gameplay provided on the wii games...best of both worlds.
BTW..I downloaded a bunch of Game demos on the PS3 and the hard drive is already half full!
Summary- ---- the wii's controlers beat the crap out of PS3 and the PS3's graphics beat the crap out of wii