I work for a nonprofit located in a heavily horsey area, so we tend to get very nice donated goods. I’m intentionally moving our herd to all Horseware blankets as donations arrive. This is partly because the inevitable volunteer blanketing fail is much safer with no leg straps involved. (And I hate leg straps!) But it’s mostly because in my experience they fit well, don’t shift, and wear like iron. Our horses are turned out daily, in groups, in all weather.
If your horse is truly wide in the chest or needs a ton of drop, I’d go Rambo. If your horse is narrow in the chest, Rhino does well there. Fairly average horses seem to do fine in any of the three lines. I have plenty of Amigos and they fit all but the extremes. The Wug design in any of the three lines will tend to narrow up the shoulders a smidge relative to the fit of an original neck.
Regarding waterproofing, all of mine get professionally cleaned, repaired as needed, and re-waterproofed annually. It’s an investment, but I’ve got a bunch of the old purple and green Rambo wugs going strong and staying waterproof with that program, so for me it’s worth the investment. I went with an Amigo Bravo Wug for my personal horse with a very average TB build.