I bought an MPP LV48 3Kw unit about a year ago, and it's worked flawlessly, but I was not so lucky with the second one I received about a month ago.
I ordered the parallel boards at the same time but there was a problem with delivery, so I installed it as just an MPPT charge controller to my battery bank. Turned it on and the first thing was an error code that the fan wasn't turning. By careful examination (I stuck my finger in the fan) I could fell that the fan blades were dragging on something.
I contacted Ian at 24/7 and he said it should be an easy fix. I did ask about voiding the warranty if I took the cover off myself, but never did get an answer.
Although not happy that I was having to fix a brand new, rather expensive piece of equipment upon deliver, I took off the front cover.
Inside I found that the build quality was awful.
The green toroid with the blue and pink wires is not secured to anything, and it's crushed the side of the very thin plastic ducting pushing it into the fan, hence the code.
I ended up using cable ties to keep the torroid away from the ducting, but if you look lower there's an orange disc capacitor that is bent over itself, probably from being hit with the torroid.
This means that the units are not tested at the factory and there seems to be no quality control or final inspection.