Haha, I bought Ariat Heritages with zippers, and about two years later the zippers popped off both. Luckily, Ariat replaced them for me for no cost, and the zippers are much more heavy duty now. Not as attractive with the big chunky zippers, but they were free, so who am I to complain??
Apart from the difficulties getting them on and off, I see why you want them, they are much more attractive. I would try Ariat again, just because I had such luck with their customer service (even though the zippers broke, which they told me was a common problem with my style, which is why it was since retired)
There is something about the outside of a horse that is good for the inside of a man. ~Winston Churchill