The WXC-50 is an excellent performer. I used mine to drive £3000 worth of active speakers and it worked superbly.
Excellent detail, good control and a discernible soundstage. The dac/preamp combination is as good as you’ll get for sane money.
If it has the functions you require then it’s still one of hifi very fine bargains.
The WXA-50 whilst having all the same functions as the WXC, has to make do with a pretty erm... not high current amp section.
So if you’re driving real speakers, I’d suggest the WXC and a more substantial power amp.
If you’re using small, background speakers, or some magical, high impedance high sensitivity speakers then the WXA is in with a chance.