plz consider these points:
Ease of Use
Investors come from all lifestyles; a superb service accommodates everyone regardless of their knowledge of computers, the Internet or trading online. Accommodations may include a navigational website, in–depth tutorials or one–on–one training.

Support/Customer Service
Trading is complicated and risky, it is extremely important that online stock trading services provide good and immediate customer service by telephone, email, instant and chat and more.