Maybe thats a more or less reasonable charge for a complex case. However, I found found that the quality of the tax preparer really varies and that price is absolutely no indication of quality. I am an accountant by education, but I don't do much taxes by trade. However, I had a lot of friends brining me their tax returns to check over and telling me they had paid $100-$200 for their personal taxes! When I took their original slips and calculated the exact same refund in 10 minutes (for free of course), their reverence for their accountant quickly changed.
Typically the young accountants are not so experienced, but are very diligent in researching deductions when they are first starting their practice. It is critical that they build their reputation, so they tend to go the extra mile. Over time, as they get more experience of common situations, they can get a little lazy in their questions (some just print out letters with the most common information and questions rather than doing an interview) and in some cases, they are no better than H&R Block (although 5-10x the price). The more common your situation, the more likely you can find someone much cheaper if you only want to prepare and file the taxes.
Where you really need the accountant is to introduce you to new ideas and to discuss tax consequences of things you are doing in your business and investments. Tax planning is an often ignored, but critical phase of the tax preparation that you should demand for the price you are paying.
For an experiment, go out and buy tax software and try and duplicate the results of the accountant through the step by step interviews. This is what your accountant is using to prepare your return. You will find the quality of his work in the difference between what you calculate and what the accountant calculates. Tax software works best with the most common situations, but does not handle special cases well. Analyze the difference and where it originates from, you may learn that preparing and researching taxes is not as difficult as it seems (you just need that kind of mind to tolerate it long term).
A lot of accountants tend to become primadonnas since the majority of people who come to them don't truly understand (and don't really want to understand) what it is they do. The way to judge the quality of the accountant is by the quality of questions they ask during the interview and the tax planning advice they give.
A good tip is to be proactive in your questions. Ask in general if you get a deduction for certain kinds of things if you feel the accountant has not covered that area. They are often too busy to go through the whole interview, so you have to take matters into your own hands.
$350 each just for the guy to fill out your forms is not too bad if you really have a lot of slips, receipts and special cases, he is asking a lot of good questions, and you are getting good tax planning advice.