First post says it all.
If truly balanced.... go balanced connections. If not... save some dough and go RCA.
I used a fully balanced amp both ways... XLR and SE, my difficulty in clearly backing one over the other was this... one preamp was markedly superior to the other... the SE preamp being the top dog in that hunt. Using the non balanced pre with the balanced amp, the sound was stunning! Far superior to the previous and same brand as the amp, balanced preamp. Both were BAT. The SE preamp, I still have is Thor MK II. Sonically, the Thor is one of those preamps you always find a reason to keep around no matter what other things come & go... well, until I hit the lottery it'll stick around... it's that good.
Of course the BAT vk5i ran about $5K less or so than the Thor preamp at $10K. Maybe that's why the RCA pre outpreformed the BAT XLR pre.
So topology is one thing. Performance levels of the connected gear is another. One can't always say one direction is better than some other... there's just too many variables.
ordinarily the saving grace for XLR is it's quieter as a rule, than is RCA... and especially if tubes are involved.
Ordinarily. Results will vary.