I got a stereo pair 5 years ago for not much money. I have other more expensive microphones, but I always reach for these when I want to mic up a speaker cabinet. I've used them on electric pianos
, organs, bass amps and all manners of guitar cabinets and combos. The frequency response is not anywhere near flat. It cuts lows and boosts highs. But it does it tastefully, minimising the need for post EQing. I am satisfied with their noise performance as well and the pair is very closely matched. I have a good collection of vintage tube amplifiers and cabs and they all seem to like the MCE-530's. I tend to mic my bass amps and I like how they report the bass very much.
The build quality is very good, they are German made. They are compact and extremely lightweight which I really appreciate. You can position them anyway you like and you can use any old mic stand without worry.
I would buy another pair, but I haven't been able to find any.
I hope this helps.