I have the MV-50 and mine has worked smooth and quiet. I thought I needed a Backup and for filling a second vehicle faster. I bought a second one like the first one from Amazon. It came last week and turned it on and WOW, this one sounded like it was going to explode from the inside and boy was it noisy. It went back the next day.
I bought a Puma and will get it and find a spot for it while using the good MV-50 as a backup. Puma is more expensive but how many times do we buy cheap over and over only to end up paying the same as a Puma or better in the long run? Looking forward to having both.
2005 4Runner, RTT-AirTop, 17' Casita SD Travel Trailer