For relatively short distances, such as you'd find in a typical home system, there won't be any noticeable difference in output levels between the two types of connectors. If you are running longer cables, perhaps fifty feet long or longer, such as you might in a studio or stage setting, or maybe in a home where you put a preamp in a room in one end of the house and a power amp at the other end, then using balanced connectors definitely makes sense; otherwise, you'll lose a lot of the signal.
There is another big difference between them: noise rejection. In an electronically "noisy" environment, such as you'd find in a broadcast studio, balanced connectors are a must, as they will reject interference almost completely. Unbalanced connectors (RCA types) do not do this well, if they do at all. In most residential settings, it won't make much, if any difference, but sometimes it will.
If you do decide to go with balanced XLRs, you'll get BY FAR the best results if you make the ENTIRE SYSTEM balanced. Think of the cables like water pipes: the balanced connectors are impervious to any dirty contaminants (= electrical interference/noise) leaking in, but unbalanced (RCA) connectors can let mud leak through into the water flow. If your system has NO leaks, then you'll get pure water out the other end, but if there is ANY segment that allows the mud to creep in at any point in the pipe chain, you'll get muddy water coming out at the end. BUT again, this will only be the case if the pipes are in the mud (=an electronically "dirty" environment). In many home stereo settings, there isn't enough interference to worry about (like the pipes being raised off the ground; even if they are porous, you won't get any mud coming out the end). I hope that analogy is clear enough.
Balanced connectors are used almost always in professional settings like studios, for both of these reasons: long cable runs and better noise rejection. Neither of these applies to most home system situations, which is why it ordinarily won't make a difference.
I recently switched my system over from unbalanced RCAs to completely balanced XLRs, after upgrading components to the point where all the units in the system are fully balanced (internally as well) and have built-in balanced (XLR) connections. I can hear a difference, but I live in a crowded city environment with some background noise, and the gear I'm using includes some really high-end stuff (the preamp alone cost five figures when new). The upgraded gear provided more of an improvement than the change in cables, but the cable change helped more fully reveal what the gear was capable of. The music emerges now out of a deep BLACK (silent) background, with very clear details.
I learned one other advantage of balanced connectors: a price limit. There are a lot of ridiculously expensive "audiophile" cables out there you can spend a lot of money on chasing 'better sound." Many of them are mostly "snake oil" -- and pretty much all of them are unbalanced RCA type. With balanced connectors, you can make cables from appropriate Mogami (or Belden or Canares) microphone cable with Neutrik brand connectors on the ends. This is exactly what is used in most studio settings, it will sound superb, and there is NO benefit to spending any more money than that, to get outstanding sound. If you don't solder or do DIY stuff at all, you can buy ready-made (balanced XLR type) studio-quality cables from those brands for reasonable prices. The whole "audiophile cable" nonsense has not corrupted the professional side of the industry.
Hope this helps.
this will be considered if I do decide to go full balance.