I recently finished a 6-week course of TMS treatment. I had a long (30+ years) history of "treatment resistant" depression with SSRIs and other medications working at times but not over long periods and with side effects that were intolerable. Have done years of psychotherapy as well.
Without going into major detail, I'd say the treatment did help and that my mood has been stabilized to a point where my mood has not fluctuated greatly since finishing treatment. It's not subtle but it's also not like I'm happy, happy all the time either!
More that my mood is not swinging as low as it used to.
My Psych recommended looking into the treatment and I did so only after many months and thinking it would just be way too inconvenient. You can make it work if a) insurance will pay some/most of the cost and b) you can rearrange your life for 6 weeks or so.
I am lucky to have supportive family and good insurance. Also I did the TMS at a very reputable hospital with LOTS of experience administering TMS.
I am tracking my mood closely to see if things "stick" over time. The MD I worked with said that a "booster" session may be needed 6 months - year after first course of treatment. So will see what happens.
Am glad to be off antidepressants and all in all would say TMS was worth it but will keep you posted.