It's bit of an impossible question to answer really. I suppose it comes down to how much you'd have to pay for a second hand set.
ANR was relative new tech back then. Having said that I've occasionally had use of a Bose X and couldn't say that I noticed the sound being any better. (But didn't have use of them side by side to compare at the same time.)
The Bose X though was lighter and smaller in form factor. Having said that I imagine a second hand set of the DC has probably stood better to wear and tear so might butter suit a second hand set.
They certainly are a long long way better than a passive set, and I very much doubt you'll be disappoint with them.
But if you were going to be paying anything like 50% of the cost of a new set, then I'd continue to use the clubs headset until you can afford a brand new set of the bose or light speed. (There isn't much difference in cost between the three.) No point in paying 50% now, and 100% later. A brand new high quality headset should last you a very very long time, and will hopefully be spread across many hours of flying (assuming you continue flying which unfortunately most don't).
As for the DC X-11, I think they were a step backwards on the 20-10XL. I think a lot of people were unhappy with them.
dp