Quality assurance (QA) is a process of identifying and correcting defects in products before they are shipped to customers. QA can be used for any type of product, including software, hardware, and services. 

The benefits of hiring a quality assurance call center include: 

1. Reduced defect rates – A Quality Assurance call center can help reduce the number of defects in your products by identifying and correcting them before they are shipped to customers.

2. More accurate product releases – If your products have fewer defects, you can release them to market more accurately, which can lead to increased sales and increased customer satisfaction.

3. More consistent customer experiences – When your products have fewer defects, your customers will have more consistent experiences with them, which can lead to higher customer loyalty and repeat business.

4. Reduced development costs – Quality assurance calls can often be used to identify and correct defects in software development projects before they are released to the market. This saves you money on development costs and headaches down the road.

Here are some other key points to think about as you compare QA firms:

1. What's the turnaround time for getting a task? How long should it take them to complete a project?

2. What kind of tools do they use?

3. Do they have tools that better suit your needs than those they offer their competitors?