Between the SX and the CR, I choose CR. The CR has a very good motor with a strong midrange pull. The SX has a gnarly motor with tons of power, and is hard for an inexperienced or even experinced rider to keep under control. Wheelies are very common on the 250sx. The frame and handling of the CR are surpassed by almost none. The CR is a great bike IMO. Both bikes have more power than anybody needs, so If I was in this situation I wouldn't decide based on motor only. The CR is light, agile and fast. You won't be dissapointed.