Of the 2 the FSC556/223 would offer better control. If you can get a bit more money you can pickup a Battlecomp from OST. They're still waiting on the import paperwork but for $150ish it's one of the best on the market. I asked the same question a while ago, do a search in this forum for 'brake'
After all said and done I decided to go with a Battlecomp.