I'm using a CTEK MULTI US 3300 on my Tradewind. I've been very pleased and it does fine for the simple set-up I have. As far as quality, I have no issues. Porsche, Mercedes, and Harley Davidson recommend them. Got it for around $69, it's a small lightweight thing, and I can quick connect to a pigtail on the trailer battery or use the clamps for charging whatever. My model doesn't have engine start capability. It's a Swedish product and on the European brochure the XS 3600 compares to the US 3300.
CTEK datasheet.pdf