XLR and RCA interconnects in the same system?

The arguement for balanced is so full of the theory, and then 'of course there is the fact that fully balanced EQUIPMENT (which naturally costs at LEAST twice as much or more) sounds better. yeah, ANY equipment that costs more than twice as much, single ended or balanced (and we will have the arguing over 'just because it costs twice as much yadda yada..)
This is one of those endless arguments with no answer for the midfi user. For the top hi end systems fully balanced electronics of COURSE balanced is better. For everybody else, it all is a crapshoot, depending on the PARTICULAR items and how they are made. ANY discussion of "are balanced connectors better.. is useless IMO. Except for those golden spooned with the highest end balanced construction.
And i await the counter arguments based on theory, opinion, and just wanting to get the two cent in.
Actually balanced is just a buzzword used to sell stuff. it has NO value over RCA at all for any system except the fully balanced from beginning to end electronics.
It is just another buzzword. like the distortion specs of amps used to be back in the 70's
Thanks.

"Actually balanced is just a buzzword used to sell stuff. it has NO value over RCA at all for any system except the fully balanced from beginning to end electronics."

Yes it does have value over RCA. It suppresses noise much better, prevents disconnect, prevents touching live wire.

I agree with Kal that benefits of XLR are independent of benefits of system being completely balanced.

I have'em all balanced now:
Technoarm rewired to have balanced(just split the ground wire onto two and connect +,- and ground accordingly 2x2=?); Classe 30 phono inputs rewired to balanced as well; CD to preamp balanced from the beginning; Tape in-out rewired to balanced(for AtoD recording); Headphone amp is with balanced in/outs. Did a 'brutal' job on Classe 30 chassis(this preamp I bought with imperfect chassis for the low hundreds). Had to eliminate 'video' and 'aux' inputs in order to increase space. Other than that, the preamp is fully balanced from the beginning with all necessary isolation of negative signal path from the ground. Piece of cake just like rewireing to convert all inputs you need. Certainly out pre to poweramp is balanced from the beginning.
There's no indeed RCA cable for ANY price that will sound better than cheap XLR.
The effect on the analogue set up was extreamly amazing: gain, definition control went high up above!
I now have a few projects of converting to balanced that I implement for friends for now (SS equipment only for now but will think of tube designs as well). I plan to charge x-amount per converting each input/output unbalanced to balanced and probably 3...4x amount for converting same for tube equipment depending on amount of chassis work.

Hi again Liz.... Actually isn't "theory" as you suggest. Anyone doing an A/B between balanced and single ended can clearly hear the difference. I guess using mid-fi equipment it makes no difference....however in the persuit of perfection, balanced is indeed better.

K4r...just plain "Nope" with the caveat that there may be some minor benefit using XLR with non balanced circuit...however, the real benefit comes with fully differentially balanced circuitry.

Can there be connectors better than XLR, theoretically?