So far I'm impressed. The 6000w 48v-230v sold out faster than I could make up my mind to buy, so I settled for the 3500w 24v-230v version instead. I'm going to use it (eventually, hopefully) to run my 18k minisplit.
The inverter is not fully installed yet but preliminary testing looks good. The unit, with the brand name of Vevor (not KFFKFF), arrived quickly and safely packaged. While smaller than expected, everything about this hybrib inverter looks and feels top quality. The fit and finish is excellent; push-button controls are user friendly; the manual is logical and readable; the set-up is easy; wire connectors are well marked and solid.
Once everything is hooked up, you can go with the preset defaults or enter a multitude of options in the settings mode. Two quiet (always on) fans draw a constant flow of air through 2 washable filters -- a thoughtful feature that will help keep the electronics clean. Only 1 minor flaw that I noticed: A blinking light, indicating battery charging, is always on regardless of whether the battery is being charged. When I hooked up the battery, the charge light automatically started blinking. That seemed odd but maybe it was me; I haven't spent a lot of time with it yet. As soon as I find a permanent home for this inverter, I'll be running it a lot. And if all goes well, you probably won't hear from me again.