Well...SCIA Engineer is an analysis package and AutoDesk's specialty is drafting/modeling/documentation. There is Robot, but if you search for it on here you'll see that nobody really uses it. So I'd say...you really can't compare them?
(I don't use SCIA, just looking up its capabilities quickly...)
I agree with phamENG that Robot is not very well used here in the US, but neither is Scia Engineer.
However, my belief is that both packages are more popular in Europe.
Note: I work for a US structural software vendor. While I do not intend to promote the software company I work for or speak ill of another vendor, please realize that I have some bias on this subject.
