For sportsman and even intermediate you can do well with a good BB sport servo. My Excelleron had Hitec HS-635 on all surfaces.

My Focus (which I didn't get to a single meet this year and I just sold it) has all Futaba digitals in it. Although a buddy of mine likes the less expensive hitec digitals. Depends on how much money you want to throw at it.

Try a good BB servo for starters and if you really like pattern you can always upgrade as you move up through the sequences. If you decide it isn't for you then you aren't out anything and have a really nice flying sport plane.