Assuming the 2 machines are close together (less than 15 feet) balanced or unbalanced really won’t make much or any difference unless you’re suffering from a ground loop (hum).
If you do introduce a ground loop, using the other type of cable might help.
Cable quality is a very touchy subject … some people swear it makes a big difference, others say it’s all nonsense.
IMO the best reason for using better-than-cheap cables is because of the build quality. Cheap cables are usually poorly made, and won’t last very long - but you can get lucky. Some of my best / longest lasting cables (10+ years) were really quite cheap.
A very popular brand is Mogami but they are certainly not cheap. Quality is excellent, and they will probably last a lifetime if not abused.
Anyway, for connecting these 2 machines at a very short distance I would not be too concerned about buying expensive cables - as long as they are above average quality you’ll be right - the cable run won’t be long enough for the signal to degrade much.
Peace,
Andy.