Oven ten years since their start and thanks to a generous So Cal BBB, Optima still maintains a good BBB rating. We would suggest that you read their complaints. Did they resolve them adequately?
If you are considering Optima, a few other things to think about:
1. What do you get for the Research Fee that they charge? Will you get the transcripts and expiration dates of your tax debt? Will they exaggerate the collection threat from IRS? Remember, since 2016, only IRS Revenue Officers (RO's) issue levies (for the most part).
2. Once your research is done by Optima, they will then propose a more comprehensive service with a bigger fee.
Here's a link to a general outline of WATAX's fee structure (you might be impressed) to see how we compare:
Fees for Tax Representation: WATAX