Hi! I'm pretty sure the MyTouch does support Outlook, but I don't use it. The things I like on the Vibrant over MyTouch is the awesome screen & I prefer Touch Wiz over MySense. However, I do like how MySense shows the last used apps in the notification drawer. I also like the 16gig of internal storage space.
I think the MyTouch is a lot better in all other respects. I love having a camera w/ flash. Speaking of flash, Flash 10.1 is a lot better than I thought it would be. Videos are amazing. I also like having a LED notification. The hardware is better, too. The device feels more solid.