I have been doing it for just about 3 months with ALA/DMSA, 5 months on DMSA, and have gotten positive but subtle results on it. Mostly psychological. Physical symptoms may be slightly better, but possibly more problems with gut/digestion. The psychological benefits, like increased confidence and so forth, have been great.
I have lots of CNS mercury, so not a quick fix. I expect to be at it for 30-36 months.
Plan for the long-term, and do it regularly, preferably on a weekly basis.