i have a real problem with non-mozzerella being used but have come to accept that most places are too cheap and want to do like a 75% mozz, 15% prov, 10% chedder type bullshit cheese mix.
imo, get that crap out of here. if you can't afford to put good cheese on your pizza, then shut the doors and go eat a hot bag of dicks. this is my one main complaint about spin pizza, they mix their cheeses and the crap becomes too damn salty because of it. so i order mozzerella only and the pie comes out with tiny, quarter sized specs of cheese.