X-Wing currently has a fairly set Rock/Paper/Scissors environment going on at the moment, which looks like this:
Turrets > Arc Dodgers
Arc Dodgers > Swarms
Swarms > Turrets
It's not a hard and fast rule, obviously a lot comes down to individual skill etc, but that's the general guideline. If you're having difficulty against a certain type of ship or list, trying its counter can be worthwhile.
This is incredibly useful to a newb like me that bought too many ships but sucks at playing so far.