Contract Pros and Cons

My current employer wants to pay for me to get cert. They want me to sign a contract for two years,(training+passing+two years). What would be some good counter points for me to ask for? What are some things I should whatch out for? I do not want tobe locked into the same salary for 2+ years either. Signing bonus… I do not want to turn them off as well. I realize it is give and take.