Plan on delays..
This is just what I heard from a former Co-worker.
A pilot I used to fly with used leftseat to get his medical back and was not to happy with the results.
Once you have been disqualified for a medical-when you try to get the medical back your entire medical history becomes fair game. The FAA will want every piece of paper work from every doctor you've seen over the years. In other words, its like opening up a can of worms. (one problem may turn into 5)
Where you find the problem in not with leftseat, but with being able to track down and recieve reports from your previous doctors. (now this will vary depending on medical history) If the paper work submitted to the feds is incomplete or they want more info- you go to the bottom of the pile and it may take a long long time to get another look. ( he's going on a year with no answer)
Leftseat- by their location is just more of a channell to speed up the process and put your paperwork right in front of the feds. When the feds have the paper work its up to them. Make sure of one thing, whoever you use dots all the i's and crosses the t's.
Keep in mind, the medical department in understaffed- the most of the members on the board of medical review in the reserves and shipped off to the desert. (from what I've heard)
I wish you the best of luck and hope you get your ticket.