I'm considering using one, now that I see how complex personal finance is :) but I'd like to find one whose motives I wouldn't have to question.
No, they certainly are not compensated the same way. Some are paid by commission that they earn from the products they sell (ie, certain mutual funds, insurance, etc.) Others are paid for their advice based on an hourly fee, or a percentage of the portfolio you have to invest.
This is a great question, because too many of us just assume that if someone is in the business, they will give trustworthy advice. This may certainly be the case, but think about it, the financial planner at your bank (who also is a mutual fund specialist - just flip that handy business card over) is employed by Bank X. Bank X sells mutual funds, GIC's, insurance, all kinds of great products. That Bank X employee is not likely to tell you about products from Bank Z down the street that might be a better fit for you.
Find a fee based planner, someone you can pay by the hour for advice, and let them help you review products across the industry. It's like asking your bank for mortgage advice...they will discuss the options THEY offer, but may not tell you about a deal down the street. Using a mortgage broker helps you find the best deal across the board.
I believe the current issue of Moneysense magazine has an insert discussing planners. Their magazine and website (www.moneysense.ca) are good sources of reliable, Canadian financial advice.