I think it's worth it. My TDF seats for The Last Ship ended up being 5th row left orchestra, right on the center aisle.
It works pretty well for my circumstances. I'm not quite close enough (nor is it cheap enough for me to burn the cost of train tickets and parking should I have no luck or good backup plan) for me to feel comfortable trying rush, especially for evening shows. However, with a few midweek off days each month or the possibility of making a show after work depending on my shift, if I see something on TDF that works for me, it's only a 60-90 minute train ride away and I can make that choice on fairly short notice.