I've been using Scottrade since I've been trading. All my shares of Baltia has been through them and have never had an issue. Haven't bought anything in almost a year but they have never been suspended as far as I know if. It's $7 per trade plus .5% commission so very low fees as far as I can see.
Only PITA, is that it usually takes 5 days for any deposits to clear before the money is ready to be used on penny stocks. Not sure if this is a Scottrade rule or same among all platforms. However, bank check deposited at a local branch is ready within a few hours!