I consider myself a moderately experienced when it comes to online trading. I've tried many of the Canadian brokerage firms. This is a review of the 2 I use most: Questrade and Interactive Brokers.
Questrade
If you are unaware, questrade is an online broker in Canada. They provide access to stocks, mutual funds options, forex even bullion.
Ease of use
The platform takes a little getting used to, but I think that's true for all online brokerage. Access to symbol lookup is not as obvious as you might expect, leaving you to fend for yourself some of the time. Canadian stocks need a suffix: .to for tsx, vn for venture.
The "View market data" button is where you have to go to see the available research and to lookup symbols. This feature is not as robust as I've seen with other brokers but it's not the worst either.
Price
Depending on your style of trading, questrade may be the cheapest broker available. Questrade trounces the competition when it comes to large volume purchases. This becomes important if you buy stocks under one dollar. The going rate is $4.95 per trade, or $0.01 per share or max $9.95. Frequently additional fees apply, but the overall cost is generally less with questrade than anywhere else. No minimum activity and good access to free data. Registered accounts can trade in USD but you get dinged with fees pretty severely.
Account types
Registered accounts available.
Margin
Rates are competitive (currently prime + 1.5%).
Options
Here the fees are a little higher. Start at $9.95 + $1.00 per contract. They provide some nice information on available options in the "View market data" section. There are a few things missing here though, for instance to place more complicated orders (spreads) you must call the trading center. No additional fee is charged for this service, but I hate calling.
Mutual funds, Forex, Bullion
I havn't used any of these services. All I know is that you cannot use their forex for currency exchange (everything goes through USD). They do offer a currency exchange service which will get you a better deal than the bank.
Customer service
I've read a lot of bad stories online, but I have to say that I use their customer service frequently and have found them to be available and generally well-informed. The best feature is the chat option. Within a few minutes you'll be chatting with someone who can answer your question. I also appreciate that the application can be completed electronically for the most part (you can scan and email/upload your documents instead of mailing everything).
Interactive Brokers
IB is a worldwide broker with a Canadian contingent. They provide access to stocks, options and futures and much more. This broker is able to cater to the most advanced users.
Ease of use
This platform is somewhat more difficult to navigate. There are multiple web based trading options as well as mutliple desktop applications. Searching for symbols is a little more natural than on questrade.
Price
Depending on your style of trading, IB may be the cheapest broker available. That said, free data is at a minimum. I end up using questrade for my quotes, even when I trade on IB (I'm too cheap to pay the $10/month) There is a minimum commission of $10/month. The commission structure seems better than questrade. $0.005/share for US stocks, $0.01/share for Canadian stock, min $1.00, max $0.5% of total value which means that the fees are generally less than questrade, but more for penny stocks with large volume.
Account types
I don't think registered accounts are available in Canada.
Margin
Rates are competitive (currently prime + 1.5%).
Options
For most traders the fee is $1.00/ per US contract, 1.50 per CDN contract. This is the best rate I've seen. The desktop platforms allow you to place complex option trades (like spreads).
Mutual funds, Forex, Bullion
I havn't used any of these services. They allow you to link CDN and USD accounts so you can use forex for currency exchange.
Customer service
These guys have a chat available too. Some comments are online about how these guys try to steal your money, including some criminal accusations. I suspect these comments are misrepresentations. I've not had any problems.
Overall
I have a hard time choosing between the two. At the end of the day, what I care about is price.
Questrade is cheapest for penny stocks and registered accounts,
IB is cheapest for options. So, for now I'm sticking with both services.