If you start on an Avid I think you would find the move to FCP pretty straight forward. No suprise given that the editing paradigm is now the same across most of the big name apps. But going the other way? Avid can be pretty daunting on first go. It takes a few clicks before you even get something that looks like the interface and it can often feel a bit closed compared to FCP.
It’s worth sticking with though as, in some ways, it feels more solid and reliable.
Avid for FCP users
So if you are thinking of expreimenting or a change of job means making the switch then help is at hand.
As part of their more concerted approach to community engagement Avid have pushed the boat out on the tutorial front. Laura Congleton has a 4 part series on Avid for Final Cut Pro Users that covers most of the basics and a few steps beyond.
Well worth a look