For me, it's all about the commissions
I think you have to specify what you are trading, how you trade, and what time frame you trade in before you can get a meaningful answer to your questions.
When daytrading, for example, fast and reliable connections are necessary, along with an order interface that you like. Commission cost is crucial. These things are far less important if you are making long term trades.
It's the same thing with charts and graphs. Long term trading, you can do quite well with free stuff on line. Short term, you probably want good, real-time charts; though I do know traders who use no charts at all. So it all depends on what you want to do.
For me, it is very important that the broker be financially sound and well managed. Some better known names are actually on the weak side in this area.
I trade stocks long term and futures short term. Currently, I use Scottrade for the former and Interactive Brokers for the latter. I've been very satisfied with both.
--geezer
For me, it's all about the commissions