The best way to find out about an SEO company before you start working with the people who own it is to read a number of seo company reviews. This will give you a good perspective because you will be able to see what people think that the company does well and what they are not as pleased with in their experiences. However, you do need to know that some people will not be thinking rationally when they write the review. You must differentiate between the honest and careless reviews, so that you are not being misguided!
For example, someone might say that the cost was far too high when the company really offers affordable SEO options. This just means that the person who wrote the review did not know how much they should be expecting to pay. You should look up the pricing for all of the companies that you can find to see if their claims make any sense. You may find that the company has very reasonable rates even though one person did not think so.
Another example may be someone who claims that the company lied when they are actually an ethical SEO company. The problem could just be a misunderstanding on the customer’s side. Perhaps they thought that the SEO work would guarantee them higher sales numbers, when it really only gave them better search engine rankings. If those hits did not translate into sales figures, it may be because they carry a poor product.