Best XLRs under $500 a pair

+1 on Wireworld Eclipse 8 XLR. -1 on Canare/Benchmark. I replaced a Canare XLR with a Cardas Parsec XLR between a Benchmark HPA4 and AHB2. Definite improvement. (Maybe from disconnecting a cable and reconnecting another, but I doubt it.) I then moved the Cardas elsewhere, replacing it with a Wireworld Eclipse 8. The replacement occurred not too long after the Canare was replaced, so it's unlikely there was any crud that needed to be dislodged, etc. I greatly preferred the sound of the Wireworld: More detail, no increase in any sort of unpleasantness, etc. Of course, in both cases, it could have been confirmation bias or whatever.

+1 On WW, Cardas is good and good resale but warmer.

Check that your equipment is really balanced sometimes it's not and you'll get better sound from RCAs.

If you want to experience a significant improvement in all aspects of your listening experience, try the Transparent Gen6 Musiclink balanced for $400/pair!  They will blow you away with their dynamics, low level detail and soundstaging ability.  They also convey more accurate tone…just mind blowing for the money 💰 

Avoid anything with PVC. 

My approach was buying used XLRs from Kimber Kable via KimberKabledirect on eBay.

I tried the Kimber silver streak versus some Mogami and better cable silver serpent and the Kimber's were noticeably better and also about 4 times the price.  

So I searched Audiogon for used cables and looked at eBay and found Kimber very active in selling trade-ins and demos via eBay at about 1/2 list price.  

I purchased KCTG 1 meter and .5 meter XLRs and I view them as my forever interconnects.