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

I have used single ended for the last fifty years. I have monitored reviews and forums on the subject... and specifically reviews on my Audio Reseach Reference gear... Phonostage, preamp, DAC, and amp RE160s. ARC equipment is balanced internally, and XLR is recommended. Most reviews notice a slightly better sound to the XLR. There has been a slow shift to XLR being noted as better across the industry. While not night and day... pretty consistently. XLR provides a louder signal, making it hard to compare with RCA. I spent hundreds of hours comparing different interconnects in the 80’s and 90’s... so I can read reviews and understand what they are saying and put it in context. I have a really good system, and am not going to waste time doing any more comparisons (especially since break-in is important and long for interconnects) So, I have been slowly swapping out my single ended for XLR... they are $4K per pop, I have one left. If I was starting today I would go XLR.

Also, as noted above it is recommended for long runs. I also have my equipment off to the side. Locating the equipment off to the side probably has a bigger impact than RCA vs XLR in short lengths, But they are all additive, so every little positive thing adds up. If you want a truly great system you want to optimize all the small stuff as well as big stuff.

I've known since the 1980's that XLR is professional wire made for professional use mistakenly adopted by audiophiles who don't really understand the difference.

XLR has all kinds of features that are really good for professional use. Professionals use lots and lots, sometimes hundreds of them, and are moving things around, making and changing connections. XLR are designed to lock, and to make the ground connection first. That is why you hear the horrible sound if you connect RCA while it's on. Professionals find it a hassle to be turning everything off so they designed it so they don't have to.

People talk about noise rejection and long runs. Get real. Yes there is noise rejection and yes they are better for long runs. But long in a home is nothing. XLR in professional use can run a hundred meters. Easy. That's long. Five meters in a house seems long to us. It is not. Not long even for RCA. 

RCA are easier to make and therefor way more performance per dollar. This is just looking at the wire. In order to do XLR properly the component needs to be fully balanced. This means two of everything. In a world where quality matters, balanced is saying spend half as much on everything. This is dumb. Only an audiophile could fall for this one.

But you can say oh Millercarbon you don't know I have my blah blah blah, and Millercarbon says yes but did you ever compare side by side the exact same component with the exact same wire, the only difference being one was RCA the other XLR?

Because I did. A guy was trying to sell me a Krell on being fully balanced. I said let's compare. But you need the same brand and model interconnects, only difference being RCA vs XLR. Thought that would be the end of that but no, they actually had the same interconnect both ways. 

So we listened. And balanced with XLR the background was blacker. The noise floor was a tiny bit lower. But there was also a loss of delicacy and detail compared to RCA. In other words it was a trade off. I would choose delicacy and detail even if it was the same price. But XLR is not the same price. It is a lot more. Factor in the cost increase in the components and it is a whole lot more.

So there you have it. XLR is another audiophile misunderstood canard boondoggle. 

Therefore, in conclusion, GO FOR IT! 😳😂😂😂😂😂😂

BALANCED much quieter for my 21 foot run more dynamic as well.But there a single ended guys that have no choice.

More great responses! I do love the locking grip that XLR offers. What I have noticed though is that some manufacturers charge the same for XLR or RCA. While others charge almost significantly more for XLR (Transparent Cable-not a knock I do love their cables).

This is awesome, thank you all you've certainly ticked the box for "having some fun" on this one :)!

Same cable same manufacturer (Kondo KSL), i like the balanced connection for a more relaxed with more body presentation as having the benefit of the extra gain. But i also like the slightly better mids and energy on top and the slightly better pace and attack with single ended connection. 
Dynamics i would call equal.
Both my pre and power amp are true balanced designs.

G