I'm one of the few ones that still main Fisticuffs.
If you haven't started learning any Cage variation yet, I would suggest you pick any of the other two, since they will give you better results with much less effort. Both are balanced characters (with some issues to fix, but it's ok).
If for some reason you like Fisticuffs as me, good luck xD
You are going to have lots of troubles opening up people defense, since you don't have access to cancels, don't have mimics plus on block and nothing in exchange. The specific string of the variation, speedbag, used to be a good tool to pressure before 06/23, but after the patch it became just a bait tool, and it's mostly used to break (some) armors. The chip bonus is hard to activate safely if you are not far, you usually need to do a hard knockdown on the opponent and sacrifice damage to activate it, which usually does not pay off.
If you want to start with the variation, here's a great guide by
@Frosted 57 :
http://testyourmight.com/threads/fisticuffs-guide.53139/
And if you want to see some of the many limitations Fisticuffs has, go here
http://testyourmight.com/threads/why-fc-is-bottom-tier-and-ways-to-save-him.57313/
Would be great if more people joined the Fisticuffs army xD It's hard to change things when few people really cares about the variation.