Just like any industry there is always going to be the good and the bad. The best way to determine one from the other is to just do a little research.

What should raise a red flag about a company.
They have no website
Their website doesn't provide an address.
They don't have their prices, policies, and guarantees posted on their site
Their prices are too low and their guarantees are too long
You can't find them easily on BBB
Their BBB rating is below C and below
They have too many complaints and some unresolved complaints.

What to look for in a company you can trust.
They have website with an address and a description of their prices, policies and guarantees.
They are a documented entity with some history and not just a name.
They have a a BBB record and it is rated B or above
They have a minimum amount of complaints and none are unresolved.
They will provide you with any information you request within reason

-----------------What shouldn't weigh in on your decision when a company has a good record:
Deposits - it's not unusual for a business require deposits and their prior customers had no complaints.
Prepayment - Their previous customers prepaid and they received their services without complaints
Testimonials - some are real, some are solicited, and some are fabricated.
References - most have been compensated and really can't be trusted.
Internet complaints - You can't trust them because most are just looking for revenge and not justice
Blogs - Complaints are made to downgrade competitors and praises are fabricated to increase business.

In Summary:
We think a company that is legally organized within a State, has a website that displays all of its prices, policies, and guarantees along with its address ,has a BBB rating of B and above with minimum complaints is a safe bet..
Don'y pay attention to the hype on a website or the opinons on a blog. Pay attention to the third party that has no vested interest and nothing to gain, pay attention to the BBB, FTC, and all of those customers that had no complaints..