StrangeKitten
Smash Lord
I practice using 5v5. I highly recommend it if you're a nut like me who likes to play a lot of characters. You can pick your main and secondaries and fill in a slot or two with others you'd like to practice. That way, you have your strongest characters to fall back on if you do poorly with a character.
But if you held a Super Scope to my head and told me to pick my favorites, my teams would be:
3v3:
,
, 
5v5:
,
,
,
, 
But if you held a Super Scope to my head and told me to pick my favorites, my teams would be:
3v3:
5v5: