I’ve hunted from a tree stand using an AR and a reciprocating CH would not be fun when aiming at weird angles. That’s the only downside to that design that I see.
I used to do a lot of hunting out of tree stands. When they’re in evergreen trees, it can be difficult to get a good sight picture from. Imagine sitting in a tree stand and having a deer step out behind you. The way I took aim in those situations is with a magwell hold and holding the rifle close. I used a red dot so it didn’t matter where my head was on a the stock. Granted this is a bit of an odd situation but it’s something that I have done.
I've been using the BCM large for several years and thought it was the best thing out there until I tried an ambi. I like being able to reach up with off hand and pull CH back is a very natural, smooth motion.
First ambi I bought was Griffin Armament SN-ACH and recently bought Raptor LT for my Creedmoor build. I hear good things about the Geissele ambi handles and will buy one of those soon too.
Mil spec was fine before I knew better, now the ambi is the way to go.