I've used the preview release 1 and 2 (still using 2), before I was using IE 5.5. Personally I like it. It has a "Lock the Toolbars" option which makes toolbars a little smaller and cleaner and I'm very picking about having as much room dedicated to the webpage itself so right there it's a winner in my book. Performance wise I can't say where it stands it certainly doesn't seem slower at work (P2-450/DSL) or home (P3-1ghz/modem). Security.. hrm don't know enough here to give it a yay or nay but one kinda neat thing is in the bottom right on the statsbar you can double click a little icon it gives you a list of the cookies that were attemped to be loaded onto your machine, where they came from, etc and lets you manage your settings in that regard. As far as stability I haven't had a single crash that was IE related, but then again I seem to have an unusual ammount of luck using MS products to begin with compared to the complaints I read elsewhere.