There seems to be two classes of weaponry there. Miniguns and traditional guns (some of them have two barrel though).
Miniguns takes time to rotate, but are much better in head on situation, but burns through ammo very quickly.
Traditional guns lack these disadvantages, but are way slower and have better endurance.
There are situations where you have two choices.
E.g. AMX A-1A has a pair of 30mm DEFA vs AMX with 20mm minigun.
Soviet planes, tend to feature traditional guns, like Gsh 23.
Personally, I prefer miniguns for general use cases, but 30mm guns like DEFA offer good ground attack potential by being larger caliber, meaning less rounds needed to be used on target (BTR 40 SPAA), and miniguns tend to be very accurate, so sometimes it can be disadvantageous in dogfight or ground attack