I was sold on Questrade for a long time. That is, until I needed client service and realized you get what you pay for ... and the obvious corollary nobody talks about is: if you don't pay for it, you don't get it. Recently I have switched to Interactive Brokers because of steady, abysmal client service at Questrade over a couple years. In contrast, Interactive Brokers offers:
i) lower trading fees
ii) lower margin rates
iii) better issue (ticket) tracking to resolve issues and questions
iv) better tracking of versions (revisions) to tax slips
v) more timely response to questions (unlike Questrade where if staff leave, your request could go cold)
vi) more accurate and complete tax slips
The most challenging thing with Questrade is not that there are problems, e.g., with accuracy or completeness of their tax slips. That's life. The issue is that there is slow acknowledgement (understanding?) of issues, incomplete resolution, and no compensation.
You may want to consider Questrade for registered accounts where your tax reporting does not matter and you won't need accurate tax slips for tax filing. I've punted Questrade for non-registered accounts in favour of Interactive Brokers.