Do some research on the brands - Leer and Century are the same company, and they make several other brands, so the caps differ in badging only. I don't remember the other brands that are in the same company, but it turns out there are really only about 3 actual makers of caps in the U.S., not the 8-10 the brand names would make you think.
Our Century caps have been reasonably good. We have the Windoor option on one side, and it's great. Our front window slides open.
Note - caps aren't totally waterproof. We have some plastic totes we keep in the bed for stuff we want to keep dry and out of sight.
1995 Airstream Classic 30' Excella 1000
2014 Ram 2500 Crew Cab with Cummins 6.7L Diesel
Sold but not forgotten: 1991 Airstream B190
Sold: 2006 F-250 6.0L Powerstroke Supercab