At the current rate of 49.33 Ref per Key, and with MvM Tickets going for 27.55 Ref, MvM Tickets are being sold WAY overpriced.
A key will cost you an average of $2.50 on the community market. Doing the math, this puts the MvM Tickets here at $1.40 worth of Ref.
This is $0.33 more than the in game store, and $0.35-$0.40 more than the community market.
Doesn't sound like much, but that would be the equivalent of selling an Australium Rocket Launcher for ~50 Keys, rather than the ~36 Keys it's actually worth.