Years ago, my wife bought me, at a pilot's friend's suggestion, the H20-10 set as a gift after my first solo flight. That was more than ten years ago. They still work well and are comfortable, but there's a couple issues. The volume adjustment binds now and is difficult to turn and the mic boom doesn't stay in place... it constantly droops. Both minor, but a little annoying. The REAL reason i wish I had an H10 series set is because there are aftermarket ANR modules you can easily install yourself in those and end up with a great set of very quiet cans on the cheap. The H20 series has to be sent in to headsetsinc.com for ANR installation, per their website..
"David Clark: The M-001-A fits all the H10-XX series.The H20-10 requires factory installation and longer installation time(no rush orders)"
At some point in the near future, I'll probably end up buying an ANR set of some kind and the DC set will become a nice spare for passenger use. Between the two models you mentioned, my preference would be the H10 . Both are good.