I had a Leer on my '05 Canyon. Back in '05 it cost me $1200 new which seemed absurd but in today's market that's dirt cheap.
No leaks that I recall, but we don't get a lot of rain.
One reason I chose Leer back then was the dual latches, ie one on each side. It's more crude but dead simple and I had been traumatized in childhood by inexpensive caps that used a central knob with poorly designed linkages that hung up or didn't engage both sides.
I should hope that has been improved over the years. I appreciated the dead simple reliability of the dual latches, but -- and while it's unquestionably a First World problem -- it could be annoying if you were in and out of the cap repeatedly....or think "oops I forgot something." Also having to lock both sides for security was kind of annoying.
Otherwise I think Leer is one of the better manufacturers.
And if necessary for your vehicle please get a logic circuit for the CHMSL. Seeing people with caps who have their CHMSL flashing with a signal just screams "hack." Yeah, one of my First World pet-peeves.....