They are used rarely, but I have MFJ-901B and MFJ-16010 tuners. I changed out the knobs on the 16010, but otherwise, no real complaints to note. They simply work.
I have various other MFJ baluns, preamps, etc. as well. Yeah, there are other brands with admittedly better QA testing, but most of the MFJ products I have work decently enough for my purposes.
That said, the current pricing of some MFJ products is getting a little "out there" IMO, even with the ongoing parts supply situation. A couple of personal experience examples....
My MFJ-784B DSP that mostly collects dust. It works okay for its intended purpose, but is it $369.95 useful? Probably not for most people. I prefer my old Timewave DSP-9 devices for usability, assuming I am even bothering with an outboard audio DSP at all these days.
https://mfjenterprises.com/collections/filter/products/mfj-784bActual usability aside, it is about the same for my VEC-162 going unused on a shelf. $299.95 versus HamScope or similar freeware. Hmmm.
https://mfjenterprises.com/products/vec-162....and thankfully those were purchased used years ago for far more reasonable prices.