I had issues with the Sierras being mostly plastic and parts popping off, but I knew better than to buy them when I did. Still have them. Karen likes them. Flew a lot of hours behind them myself too. Not terrible but parts popping off anything that costs over five Benjamins ****es me off. I have studio headsets that are over a decade old, smaller, lighter, and WAY cheaper that wore out the fake leather earpieces and never had anything pop off.
Finally upgraded to Zulus after waiting forever to see if Bose would do Bluetooth right (eventually they did, but not soon enough), Sennheiser could get their ANR up to snuff (they are nice folks and sponsored a number of events at OSH that really show a good community spirit but alas, the product just can't seem to "get there"), or if DC would ever come back to life and do something modern (still have pairs of DCs that have flown with me since I was 19 -- I really wanted to support them but they're lost in the woods as far as GA goes. They have their big contracts or whatever keeps them busy and they are just nearly irrelevant nowadays...), so... Zulus it was.
They're "fine". I wouldn't put them in the same long term quality category of the 23 year old DCs, but for the modern headset purchaser, they seem to be the only game in town.
Oh. Was interested in those AKG sets that are new, but couldn't find a pair to try on for an extended test for pressure points and decided I just didn't want to deal with an "off-brand" in case they went under, since aviation isn't their main product line. And for studio headphones I'm a dyed in the wool Sony Pro series fan. So that killed any possible long term relationship with what otherwise is known as a pretty good brand name in the studio/audio world.