I have two Wen inverters and one Champion inverter so I'll chime in. The larger Wen inverter is the GN400i which is a mid-level model. The smaller Wen is a 56225i. I have used both of them during outages and they have worked fine. The only thing I don't like about the 400i is that it has only a 2 gallon fuel tank which means I cannot go all night without having to refuel. I found a workaround that solved the problem. I can run a fuel line from a larger tank that will allow the Wen to run all night. I have only used the 56225i for short outages. I've had no issues with either unit.
I also have a Champion 200913. Wal Mart was running a sale on them for around $550 so I scooped one up. I did have a problem with it when I got it. The fuel valve leaked internally so when I shut it off, it kept delivering fuel to the carb. I contacted Champion CS and they were great. They shipped me a new valve assembly and that solved the problem. Plus, the tech had a lot of great advice for taking care of the model. Otherwise, the Champion has also run well when I've used it.
Back in 2021, the Champion and the Wen 400i were running together in parallel after Hurricane Ida. I had to modify a Champion parallel kit to get them to work together. The setup produced plenty of power, all that we needed to run a fridge, two window a/c units, TV, fans, router, lights, and chargers. We were very comfortable. What's nice about the Champion is that it has a four gallon fuel tank so it would easily run all night when needed.
I don't think you can go wrong with either model, to be honest. If you order direct from Wen, they ship for free and the price you see is the price OTD. So that is a consideration.
My next inverter purchase will likely be a Honda because Paul is going to make me buy one. I'm trying to resist but Paul is Borg. And we all know when it comes to Borg, resistance is futile.