To share my experience with the Mahi Mahi m7.
I ordered one from mercantilo del ukulele (who say they inspect and set up all ukuleles before shipping) after seeing this review (great review btw!). And the first one I got was a bit of a dog, a lot of blemishes, very sharp frets and the nut wasn’t installed properly.
After sending some emails that went unanswered I called and was able to set up an exchange, which went semi smooth.
The new one I got is a lot nicer, plays nice, sounds nice and looks nice. Love the neck profile.
I’m going to have to file the fret ends a bit (just need to find my files, haven’t done that in 10-15 years). Overall it’s a nice ukulele for the price, but expect to do work on it.