I ordered my tickets for the end of April through lastminutetravel.com and they beat everyone's price. We got 5 day park hoppers for five of us for only $723! It saved us over $80 from Ares and over $100 from the DLR site! There were no fees, just straight up price of tickets, well worth the savings!
I called DLR to ask if they have had any problems with redeeming tickets from LMT and they said that they haven't heard of any, so I feel confident in ordering through them.