I have access to Datek Direct... nothing great.
What I don't like about this most is that there is no dynamic order confirmation screen. Instead, you have to keep refreshing your daily activity page to see if and where you were filled.
In my opinion, Datek is a very good broker for position trading, but NOT daytrading. What happens when their website goes down for a half hour--and their phone lines are all busy? This has happened to me, by the way...