How do you intend to use the bike?
I preface what I'm about to say with the caveat that there are a number of very happy FX riders on TE who have not "outgrown" their bikes. There is nothing inherently limiting about a bike like the FX.
That said, I'm one who quickly went from the FX to a road bike. It took all of about two months if memory serves. Once I got my road bike, I never rode the FX again. Don't get me wrong, I think it's a fine bike. I just like my roadie that much more. I'd emphasize, though, that my roadie fits me and has a comfy ride. That's the key to the comparison.
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher