Obviously when someone is holding that's the best deal but if you have to go commercial the reason I said to go TM is because Seat Geek and Stub Hub are often just reselling TM tickets and you will pay the same fees + the reseller fees.
I mentioned getting burned by this so here's what happened: I was visiting my sister over thanksgiving and the hotel my mom booked for us was across the street from the Pond so I decided on a whim to go to a game. It was 11:30 and game tipped off at noon, so I looked around for best deal and bought about 11:45. It took 45 mins for the tickets to be delivered and so I missed the first period. Would not happen if it was a private seller listing on one of those sites but because it was ticketmasters there was a whole process which caused a delay I am almost certain would not have happened if I bought direct or frankly just walked up to the box office which is probably what I should have done.