Benefit of a Newer (Used) DAC - "Bang for the Buck?"

Despite having a SO who fails to understand why anyone would spend more than $100 on a “radio,” I’ve managed (over several years) to covertly assemble a fairly decent home audio system.  (My prize acquisition being a $500 set of LN Belle Klipsch loudspeakers off CraigsList).

At any rate, relying on quality used equipment that is past its technological “expiration date” has, under the circumstances, served me reasonably well. However, I’m now to the point where I’d like to (again) update several components – namely, the DAC.  

I’m currently running a Cambridge CXC transport through a Genesis digital lens and a Muse Model Two DAC – both of which, while fully functional, are fairly dated.  Realistically, how much noticeable impact can I expect from a newer (used) DAC – like a Bryston BDA-2 or MHDT Pagoda (for example)?  FWIW, my current setup does everything I need it to (i.e., play Red Book CDs).

In advance, thanks for any advice/feedback.