TD Ameritrade is a great platform and now has no commission trades.  They have great charts and support.  I use their charts to day trade and they can be a little iffy trying to place an order at 8:30:01 and get back out at 8:30:05, but market open is the only time I've heard that it's an issue.  I trade on Lightspeed mostly, but I'd expect you will be fine, especially until you find that orders don't fill like you expect.