IB - Nelson, I'm still with IB and have been for years. As hweb noted, that affiliate nonsense where they restrict you from trading a stock that's in your account is a real pain in the a$$. You have to submit a reply telling them that you're not an affiliate, and sometimes it takes a few days before they lift the restriction. It has happened to me quite a few times over the years. They have even done it on short positions. It seems if I avoid holding decent-sized positions in low volume or low market cap companies, I don't get hit with their restriction. The other thing that drives me nuts with them is their price-capping. If you enter an order that they think is too far away from the current market they price cap your order.
Here's what keeps me with IB:
1. Their commission plan is direct access. There is no middle man like the no-commission brokers. This means faster executions.
2. You can short otc stocks.
3. You can trade or have standing orders executed as early as 4am eastern.
4. They now have overnight trading which covers other hours. It's more limited as far as market participants, but it's definitely useful.
5. They pay a good rate on your idle cash with the commission plan.
6. They offer hidden and iceberg orders.
News 
Market Data 
Discover 
