Whether zippers are frowned upon or not depends on the hunt. If it is a "fashion police" hunt you may get grief. We, including myself, have quite a few members with Mountain Horse boots with zippers. As someone once said, if they notice what you are wearing as you gallop by then they are watching the wrong thing.
I'm in the minority, but I love my Dublins. I have the Aristocrats, which I believe is a discontinue style at this point, but they're awesome. I abuse the heck out of mine, but they clean up and look new every week.
Dehner. No question. I have two pairs of their black strap tanker boots I wore every day for 20 years as an armor officer in the US Army. Then the Army went to tan (suede) boots, I had a pair made, and have worn them every day for the last seven. I have a pair of brown field boots (three-buckle) for daily riding and informal hunting and a pair of black dress for hunting (worn with Dress Blue uniform). The tanker boots (black and suede) have held up through four desert deployments, Desert Storm, Iraqi Freedom and Afghanistan. I'm still wearing them every day.
They'll bury me in my Dehners, and I will have a pair caparison in the riderless mount behind my caisson.