I spend a lot of time on these forums (Actually more time than actually playing), and I have read a ton about different lists. People are always talking about what lists are good, too good, or maybe even broken. And this usually comes down to what ships to put in your lists. I even read a thread where the poster though banning Phantoms all together was a good "fix" for the game.
Be it Phantoms, Falcons, Firesprays, or TIE Bombers these discussion usually focus on ships, and then what upgrades to put on them.
I wouldn't say that I am a great player. But I play competitively in tournaments when ever I can fit it into my schedule. I can say that after the first time I see a ship, I have never thought "Oh crap phantoms" or Decimators, or Falcons or any type of ship. Sure I have lost games to all these ships, but I have beaten them all too. But there are lists that almost always loose to. Synergy Lists.
Synergy lists aren't built around making any one ship good, but about making your ships work together to some useful effect. Last night I fought in a tournament and the only time I lost was to a list with Wes and Wedge with opportunist.
I think I have never beat a Synergy List in a Tournament. I don't know if anyone else has had similar experiences, but I actually think this is a great thing about this game. The best lists aren't the ones that take any kind of ship or even any kind of upgrades, instead they are the lists that work together to become something more than the sum of their parts.
All that being said, Synergy lists do have their flaws. Firstly, like any great X-wing tactical lists, they can be hard to fly. Mistakes can have compounded effects. Secondly many synergy lists can be disrupted by taking out a ship or two. But figuring out just which ship to kill (If you have never fought the list before) can be tough. Also the best synergy lists seem to work in a circle, where every ship seems to boost every other ship. No one ship serves as the lynch pin for the list.