All things being equal (hypothetical) which do you prefer, XLR or RCA?

This construct of "which do you prefer, XLR or RCA cables" is kind of backwards. Choice of XLR vs RCA (single ended) cables follows the design of source equipment such as DACs & preamps, in which either balanced or single ended designs may be executed for reasons best known to the designer.

true - but there are equipment/system choices that can be made using one method or another ...  thus the question is relevant to many

If you can get your DAC or preamp near the amp there is no benefit from a balanced connection, conversely if you want to drive mononlocks near the speakers balanced is likely the preferred option. In high res systems with short cables my experience is that balanced depending on implementation at worst is more sluggish or in the best of all worlds gives no discernible benenfit. Longer runs, balanced wins.

Xlr vs rca.  No one can tell the difference when runs are shorter.  AB testing impossible due to volumn level changes.

if i had a choice i would go xlr, cause its alot cooler to say i use xlrs.

so go for it

Either.

That's why 'gender-benders' and whatwherewithall exists for your purchasing pleasure.

'That' is all rca....whereas, 'this' is either xlr or 1/4" phone.

Except for the f/o, that's pretty straightforward....

One adapts....*s*

Hello, I am running a Parasound P6 Pre with Parasound A21 amp feeding it with Yamaha cd-s1000 sacd player, and  a musichall 7.3 with Ortofon Black 2m  for my turntable, all feeding my B&W  803s's.
I am running Audioquest Water RCA's, and XLR's. I did notice the different between the RCA and XLR. The XLR's  have a more open sound stage compared to the RCA's . Imaging was better. But i only can use the XLR between the Pre and Amp, every thing else is RCA's.
My other system Mcintosh c42 pre and dual mc162 amps. I really noticed the difference between the XLR to the RCA's.But it also depends on the cable, not all cables are made the same or sound the same.