Well, I spent a lot of years using fruityloops, I was using it since 2.3 or something, and when I made the transition to reason... well suffice to say is that it wasn't very pleasant, specially with the piano roll (I use it normally now and actually find it more efficient than fl's, it's just a matter of getting used to and knowing how it works and the proper shorcuts).
However what kept me going at it, and trying to learn it was how fun it was to mess around with the parameters and cables, this interactivity level is something that keeps it fun and fresh imho.
So yeah, for someone accustomed to some other software, they can have a hard time getting into Reason.