I have up close and personal experience with two gas generators.

My CERT owns a Honda EU2000i. It's very small, relatively light (you can pick it up and carry it one-handed with some effort), fuel-efficient, very quiet, doesn't seem to burn any oil, and apparently lasts forever. Because it's an inverter-based generator it puts out true sine wave AC and can be used for sensitive electronics.

Personally, I own a Champion 3500W (4000 peak) model. It's about three or four times the size of the Honda. Don't even think about buying it without the wheel kit. It's fairly quiet but much louder than the EU2000i. Observed fuel-efficiency has been very good, and it doesn't seem to burn any oil. I haven't used it very much so I can't give you a sense as to its long-term reliability other than to say that it always has started easily and seems to be built to last. Mine is not an inverter model, so it's not recommended for sensitive electronics.

If you have the money and your load is less than 2000W, the Honda cannot be beat. If you're cheap (like me) or have a larger load to be concerned about (also like me) I have no qualms about recommending Champion.

I'm not affiliated with either company other than as a customer.