I'm surprised Silverlight's actually that high up.
I heard version 2.0 is a lot better, i wouldn't even touch version 1.0.

Although i have never used it myself, the one worrying thing i have heard is the it can be very gpu intensive. Most places i have worked all the machines have a fairly crappy graphics card spec.

Flex is great to program with, so i am interested to see if Silverlight is any good.