I've only seen one off-brand crossbar kit on amazon and it didn't review super well, so far people have only reported being happy with the mopar ones (which I think are made by thule?).
I'm getting pretty close to simply fabricating my own. The OEM kit is too expensive, aftermarket hasn't caught up for them yet, might as well do it ourselves. I'm way too busy to start on that any time soon though. For the moment, it is slim pickings, spreading the wallet and getting the OEM kit probably the best way to go at this time. If you have a small utility trailer you can use, could wait for better aftermarket options.
You definitely can't just toss stuff on the roof like my old SUV, you can feel the thin metal flexing under your hand when washing the roof. Its meant to have any roof cargo supported by crossbars and nothing touching the actual roof it seems.