I must admit, it does look sleek.  The features isn't much new, except maybe for the annotations being in the cloud. ( Not that my PRS 505 supports annotations) 
Anyway, I  wondered if it supported BN's DRM, since that would be a sign that T1 support it. So I added one of the freebies I downloaded recently, but it couldn't open it.   Not that I really expected it too 

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Oh, and the way it Author Sorts, and that I cannot change it annoys me.