Victron Energy, ALL THE WAY. We've used them all, Xantrex, Guest, Charles, Magnum, ProMariner, etc. Nothing does the job as well or lasts as long as Victron. Xantrex used to be THE guys, but their support went down the drain. Charles makes a good product, but overpriced for what you get. Guest is absolute junk, and Magnum and ProMariner are the budget options for customers who don't even know they have batteries on their boat. Talk about an endorsement, we just put a Victron MultiPlus Charger/Inverter in Greg's boat last year. 80A Charger, 2000W inverter. I wish he would have gone with the full remote and monitor, but he just went with the basic on/off switch for the inverter. Very cool system, we actually hooked it up to a laptop and configured each bank and set different parameters for its other features like its PowerAssist, which will actually boost the incoming juice from a shore power inlet if it's less than 220, which happens at a lot different docks.