I'm new to the site, and have only been trading for the last month.  I started with Sharebuilder and am in the process of switching over to Scottrade.  I found that Sharebuilder's commissions were much higher than what I was willing to keep paying.  Also, when I was purchasing I didn't see the options to do any Limit trades.  It helps that with Scottrade, my local branch is across the parking lot from my office.
,Jeremy