I put some m2s on my daughters bike – got them for about 30quid the set with discs on one of those 20% eBay deals that pop up no and again.
And for the money they are bloody amazing, really put the 2015 xtrs on my mtb into perspective, as power wise there not much between them. There are things that remind you that they are at the cheapest end of the market – weight, levers being to long and the hoses feeling like there made from mixture hose pipe.
As they went on my daughters xs 27.5 frame I had to shorten the rear hose, but the set came with the bits to do so and in the end after a quick cut and plug, I didn’t need to touch them after fitting.