I have had one on my boat for the last two years.
I am very pleased with it. It seems to get my batts up to a very high state of charge very quickly. My other main charging
source -- a Victron 70 amp charger/inverter -- takes endlessly long to charge once the batts are up to 80% or so. The Adverc SEEMS to get the batts up to 100% quite fast.
I say SEEMS because I am not completely confident in my measurements of battery
state of charge, but subjectively I can tell you that short periods of motoring do really seem to charge the batteries well. The Adverc regulates a big Leece-Neville 110 amp (x 24 volts) school
Adverc claim that they have a special technology where a high voltage is used for short periods of time, switching back and forth between a lower voltage. This way, excessive gassing is avoided (high voltage is switched off before it gets to that point) while the batteries still get a high voltage charge, late in the charging
cycle. I can't say that I am 100% sure that it really works like this, but subjectively it seems to be true.
I consulted with a number of Adverc users before I bought mine and heard nothing but the highest praise for it. So it SEEMS to be a good piece of kit. Certainly, nothing I have experienced with it contradicts that.