Here is the list of games I play using steam.
And here the time for the games I play most of the time.
Plus the 800+ hours I have put into VC-MP, every clan has their pros and con, while VU is much more active than ULK, ULK may have full insane bloody agressive players LOL, we can't put the 1st 2nd 3rd place without categorize the clans example:
Most actives clans:
VU
ULK
DZ
BKS (all lag waves cout too)
Most assassines or agressive clans:
ULK
DZ
VU
To be honest DZ got a few good players.
Most laggy clans:
[LBR]
(BKS)
[RD]
Composed just by brazilians this one since we are talking about clans
Now as I said before, we can't place clans in 1st, 2nd & 3rd place, simply because of the pros and con of every clan, I honestly can't rate any clan if we do it generally there is no way.