I am a moderate trader and so their fee structure of $4.95/trade is very appealing since other banks charge way more than this.
I also make use of their Bulls Eye research tool which is available to all members when they logon. It gives you tips and news on what the next hot thing is going to be. It's actually made me money on a few occasions.
Questrade also insures accounts so there is nothing to worry about. Also funding and withdraws are very easy to do. You can do so in a variety of ways such as EFT, wire, cheque, and more.
So far I am loving Questrade more and more by the day. There is always something wonderful to explore and use.
If there is only one brokerage firm you should join to make your trades it has to be Questrade.