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

From the top of my head: XLR has 4V rms signal level, RCA has 2V rms, so the signal-to-noise ratio (everything else being equal) is better for XLR. Second, the balanced connection means that interference on both signal lines would be cancelled out at the other end. That means that any kind of interference has less impact in an XLR setup. It also means that one bit more accuracy in all the analog signal accuracy that your expensive DAC has distilled from digital source ends up in your analog domain.

TL,DR: XLR is one bit more accurate. 

OTOH: there is no "everything else being equal" in audioland. Listen before buying, as always.

We are talking about 300.00 usd in cable no matter the cable manufacture. The fact we are even comparing cost is kind of moot for me. I suppose if I was buying someone’s off the shelf cable that would be the issue.

Because I don’t buy anyone’s brand I have the option for either balanced or single ended. I have the proof in the pudding here. Cables REALLY matter, the difference is I make my own, again it is REALLY NOT rocket science.. It is actually hooking up some wire ends to terminal ends.. OK you call it what you like.. THAT is what it is.. You may have to twist this and heat that, but guess what, it is still under 300.00 for 20 foot cable run of the highest quality cable on EARTH....

Depending on the gear some sounds different, but I have the option to change cable constructs a lot easier than most.

THREE kinds that’s all I found that work differently for RCAs and XLR.
Not talking about active shielding only shielding by design (weave) or wire twist...

I haven’t tried gold, aluminum or lead, BUT Copper, Copper clad and Silver are pretty predictable. The type of cover is predictable. How they are going to sound and how they are constructed make a lot of difference, but predictable. The type of copper NOT so much.

I keep seeing OCC is better, LOL I have tested the sonics on it until I almost went deaf.. OCC copper with teflon OFF the spool as direction is only .000X % less O2 free. I can’t hear the difference.. with RCAs or XLRs OCC vs OFC.

Speaker cable or copper/clad...that’s different... They sound different... OCC vs OFC

My answer is both, NO OR...

Appreciate all the great responses, thank you All! Sounds like XLR is for the most part what most prefer. Like I said I have gone balanced now and will not go back I was just more curious than anything else to see what most here prefer. But I definitely appreciate those of you that have done comparisons and shared your findings in your own systems, so thanks for sharing!

Locking grip?, sluggish? 

Over short distances they sound exactly the same. Over longer distances balanced cables have a theoretical advantage but I doubt any of us could reliably tell the difference. XLRs are certainly more ..hip. They lock in place which is nice. For those of us that use mono amps behind the speakers they could be considered mandatory and this is where they first entered the consumer Hi Fi chain then got generalized. They make sense for turntables which are balanced from the get go. Sound different? In your dreams maybe.

Many comparisons with various gear over 2 decades shows that dynamics are better, contrast is better, low level detail is superior and bass definition and impact are improved with true balanced XLR cables used with true balanced gear ⚙️