This question comes around every few months and reading all the responses I have to say that there is no clear winner. I have heard horror stories on all brands and I have heard people say how much they love all brands (okay maybe a couple never got any love).
I have a Majestic (think it is from Thor) and it is amazing, great build and nice features from any unit let alone from a rental. I have seen other brands that I would not spend my money on no matter how cheap. It really is buyer beware as a good brand can still have bad units. If you are looking take a look at a unit that fits your needs and if you like it then go over it with a fine tooth comb (don't let the salesperson rush you, IT IS YOUR MONEY) and have a mechanic and a RV tech do the same.