I saw this very useful page for comparison of major features between popular version of Windows mobile.

Its interesting to see that there are not many featues added in 6.1, rather thats why its 6.1 not 7.0 :).

One intresting and much required feature that I noticed in 6.1 is auto pairing with bluetooth headsets. Who ever have had exprience with pairing their headset each time once it goes out of range would appreciate this feature. And this page is very nice to see the quick list of features that you will be intrested in, especially if you already familier with Windows mobile ver 6.0 or 5.0

I am waiting my finger's crossed for my T mobile Vario II update, which should be available here soon

-Rujith