We have quite a few forum members towing with Subaru Outbacks. A significant limitation is the 200 pound tongue weight
rating. In order to keep tongue weight
in the recommended 10-15% window for stable towing, that means you are limited to a 2000 pound trailer. Most 13' molded fiberglass trailers fall
within that range. However, some with front bath, twin LP tanks, and a battery
will exceed the tongue weight
limit. Some wise loading is typically required. Putting that Dutch oven at the back may help!
Anything larger than 13' is probably a no-go.
Best? You'll get different answers to that. It depends on your budget and expectations. There are currently only five manufacturers producing 13' eggs, Casita
having recently announced it is dropping the 13' Patriot model. Remaining options are Scamp
(far and away the most common, simple and basic in standard trim, semi-custom wood interior available), Happier Camper
(a recent addition to the field, modular user-customizable interior), Weiscraft
(a narrower rear-entry unit), Relic
(semi-custom, vintage styling), and Armadillo
(semi-custom from Canada).
Of course there are many used and vintage options.
Best wishes finding the trailer that's right for you!