The quality and sonic characteristics of the preamp are of the highest importance and the interconnect capabilities are of a vastly smaller or of no importance. But the world is slowly migrating to balanced. On some equipment they may sound slightly better.
For instance, I compared balanced and unbalanced on my current Audio Research equipment and I couldn’t tell the difference. Audio Research recommends balanced, but does a great job of converting to non-balanced.
If all else is equal... and it virtually never is... you want the option for either. There is a slow migration from unbalanced to balanced. You can save money by using unbalanced since often quality interconnects are much cheaper.
If I could get an older high end Conrad Johnson preamp for instance, that did not have balanced over a much lessor preamp with balanced. I would do it.