From (bitter) experience, a bad sharpening job can ruin a saw blade and give worse results than before sharpening. The company that I used for years went out of business and I looked for a replacement. Fortunately, I didn't send one of my better blades out for the initial test.
Carbide Processors has been recommended by posters on another forum that I frequent, and I'm probably going to send them a trial blade in the near future - again, I will send a mid-level blade that has given acceptable cuts to have sharpened and evaluate the work before sending one of my better (more expensive) blades out to be sharpened.
Here is a link to their web site and a page which defines some of the terms, there are other pages that describe the process and their quality requirements. Saw Blade Resharpening
Carbide Processors has been recommended by posters on another forum that I frequent, and I'm probably going to send them a trial blade in the near future - again, I will send a mid-level blade that has given acceptable cuts to have sharpened and evaluate the work before sending one of my better (more expensive) blades out to be sharpened.
Here is a link to their web site and a page which defines some of the terms, there are other pages that describe the process and their quality requirements. Saw Blade Resharpening