I tried it out earlier and it was pretty nice. I open the same five tabs in FF3 and Chrome, and Chrome was much lower, around 66MB and FF3 was around 130MB.
Also, I ran the Slickspeed tests, and the results moved from 100+ms totals to less than 100 ms totals.
Looks like a great browser so far.
It actually looks worse then IE7! I hope they fix this in the final release.