The top tier quality brands Airstream, Bigfoot, Oliver and Escape don't have roof leaking issues because they don't use membrane roofs. If you have a thin piece of rubber or TPO with seams all the way around you're going to have leaks eventually.
Top tier brands also don't have slide issues because they don't have slides. None of them have wood roof decking and with the exception of airstream don't have wall studs. Some things are nice not to have like corner seams, delamination and additional caulk points. Sometimes less is better. Lack of a slide is the reason I don't still own my BigFoot. There are always trade offs.