A liner is required. They're available from stove shops, hardware/home improvement stores, or online. Some of the online places offer free shipping, which is a good deal for such a bulky item. Modern stoves rely on a strong draft and that draft is supplied by a properly sized flue/liner.
I'm happy with my Lopi but wouldn't shy away from most major brands. If I was doing it again I would take a serious look at Pacific Energy stoves. Lopi uses fire brick for their baffles, and Pacific Energy has a stainless steel baffle. Fire brick baffles are probably used by other brands, but many use some kind of ceramic fiber board that can warp and wear out. Probably easy to replace, but I like the brick or steel ideas better.
I don't have any experience with catalytic stoves but they are known for getting much longer burns.