Heres what I would do...go to training mode, go thru each and every character (it will take time, not that much tho.) and do all of their moves. Do all of their target combos, figure out wich combos lead to wich specials. Maybe look on here for each guy and do some of the combos found. Once you do this with EVERYONE you will get a good sense of who feels right for you. You cant just look at a post that says "reptile is top tier, look at these sick combos!" cuz guess what, you might not be able to do those combos cuz u will need alien technology finger speed. So some guys will be useless to you. However, you might use liu kang and find that all his moves flow for you and u can bust out all sorts of stuff.
So try everyone u can possibly conceive using and find out who comes natural to you.