I've been fortunate to be running the MT7's for almost 3 years without any issues. Yes, bleeding them when new was a bit of a pain and took a couple of hours to get them air free - but since then, they've been trouble free until now.Welcome to Magura Hell. If there's anything Magura needs, either design in more pad clearance or use pad springs to aid retraction, like most other brands of brakes. Also a system that isn't so adept at trapping air when bleeding.
I have 2 sets of MT7 on 2 bikes I ride regularly. I find it shear luck if at least one brake isn't making some kind of squeal. I've been running these brakes for 3 years and all of the problems are just commonplace, just look it up, tons of reports of this.
It's not you, it's not the LBS, it's Magura. They need to refine the design to make life easier on us. Sooner they admit to the flaws, the better. I keep running them for a few reasons:
1. I own 2 sets, have a spare, have multiple rotors, bleed tools and lots of royal blood.
2. The feel of Magura brakes is ideal to me, power comparable to Saints but with excellent modulation.
3. Consistent bite point, no wandering levers, i.e. wandering pistons. Never mushy feeling like some SRAM models.
4. Interchangeable lever blades--this is huge to dial in your own personal ergonomic preference.
I'm in the same boat as you with points 2, 3 and 4!
I love the power and modulation - and always find them to be consistent. I put the carbon levers on mine, which help with cold finger tips during the Scottish winter.
I'm crossing my fingers and toes that they play ball over the weekend, and ride without any shrieking noise!