I've seen nearly every Youtube videos, many reviews/previews on sites, blogs, posts here and so on.

My 2 cents are:

1. It does have true multitasking and I didn't see much lag from the videos. Definitely better than any other phone it seems.

2. I don't see any noticeable tearing in this video. Am i missing something here? (I think this is retail version)
http://www.youtube.com/watch?v=15IC-ftd5uI&1&fmt=18
See around 2:34 for some side scrolling.

I don't understand how you can be disappointed about the phone yet.
This is more of a mobile computer and not a phone. For me at least.
So expect some major changes over the next few firmware updates.
(And expect TONs of new device-enhancing apps / widgets)