Providing you give them the necessary documents, they should be able to provide you a mathematically correct tax return. While cheap, they don't do a lot of probing for deductions and their is little or no tax planning. Do it Yourself Computer Programs - Good for those that have simple returns and want to do their own taxes. I have to over-ride the programs and fill out the forms myself whenever I use one. However, most of the programs have all the necessary tax forms and do a good job of adding correctly and printing the return.
Some programs have a little tax planning built-in.
You should get a free initial consultation, prior to any work performed. Ask them what you could do different to save money on next year's return. Shop around and find one you like.