I use them, and like them. I researched the online brokerages and this was the top rated. Granted, I haven't tried any others but Questrade has been easy enough to use, once I got the hang of it, and meets my need for a constant stream of data.
the one thing I would say - if you plan to do regular, small contributions it's awkward, as each buy/ sell is subject to a $9 fee. I think some products are exempt, but i'm not choosing what I buy based on a one time fee. but $9 over and over adds up. so if you contribute frequently maybe see what else is out there?