Are you someone that always does their own taxes? If so the cost of your tax preparation is time. If you have plenty of time to do your taxes and they are relatively easy to do (not a lot of deductions) then you won't have a need to go to a major tax preparer franchise chain. For the rest of us this is a much cheaper option that actually hiring a tax accountant.
What can you expect? They will usually ask you a series of questions to try and ascertain what forms they will need to use to best serve you. If you don't have all of your tax forms W-2, 1099, and proof of mortgage payments and children's birth certificates they may make an appointment for you to return. If you know that there is an actual deduction that you can take make sure to speak up and let them know. The questions that they ask are basic and won't cover everything. They don't know your day to day lifestyle and the financial decisions that you've made.
If your taxes are really a burden every year, you should really consider getting an accountant on retainer. The cost would be worth it to you. If you are a small business owner you don't need to waste time doing what you aren't good at. You should delegate this to someone with a lot more experience than you have and actually know what they're doing. You can do what you do best which is running your business. If not then not only are you losing sales by not talking to potential customers but you might end up owing taxes because you didn't take all the deductions that were due to your company.
Tax preparers are people too. They are helpful and want to get you the maximum amount of refund that they can for you. They work in stressful conditions. And people expect them to work miracles in short time frames. If they don't do a good job they know they you won't come back next year. That is why customer service is the utmost thing they can provide. If you enjoy their service you might even recommend or provide a referral to others.