The Telex 850s work pretty well. No batteries but....the ANR circuit is powered off the 5v mic bias voltage. Some airplanes don't have this, and even some airplanes of the same type are wired differently, and don't supply enough for the ANR or the mic to work. On my last two fleets, there were a handful of airplanes it didn't work on, and you're relegated to using the ship set.
The DC-Pro X looks like a nice unit and being battery powered, shouldn't be an issue.
You can roll the dice on the TSO issue. One hyper-anal Fed and you on probation equals no bueno.
Half the fleets at my current shop has old school DCs with 1 ear cup (no kidding, and some guys use them), and the other half has Telex 750s, which are very decent.
I've seen everything from A20s to those little 1970s glass mics that clip on your eyeglasses and a separate molded ear piece. It takes all kinds.
Nu