I once had a very short and prompt discussion on the topic of Support masters versus Killy masters, with both of us agreeing at the time that Killy masters on the surface appear to have the advantage in terms of gaining and denying Vp; whereas a support master can easily score 10Vp but maybe have trouble against preventing the opposing players.
In my relatively limited and casual experience, this seemed to be the case. Yan Lo can and will score 10vp unless his crew is taken out to the point where it's no longer possible. Any common model (read non-peon) can score marker based schemes and every faction has a tanky model to stand and take hits whilst accomplishing interact actions or protecting future Vp investments but after that? How are you going to deal with your opponent scoring just as well with their models? It's something which killy crews can take advantage of easier than support masters
Most players I've pitched this question to have stated that masters being denoted as simple Death-dealing or Support is much too black and white which I stand to agree with. Rasputina is very killy but with Ice Pillars and handing out Armor +1 with Silent Ones healing alongside the fine Freeze Over, one could easily argue that hand-in-hand with sheer unadulterated death, that she's also great at supporting her crew allowing them to win games.
Nicodem is very supportive but with all his summons being buffed to the teeth and a general disregard for them un-living for too long, his crew can also be described as killy. Ramos creates spiders and does a bunch of Ap-oh-who-cares (I'm not a fan) but when his spiders are positioned with care, taking down a Df3 or less henchman with constructs having every buff they need is a simple job. Thus it comes down to what scheme pool is on the table and taking it from there.
How often does a table wipe happen in your meta? Many out there might be in agreement that winning a strategy with no one left across from you turn 3 onwards is the easiest thing ever (in most of circumstances mind; Collect the Bounty with a bunch of schemes requiring interactions or keeping your opponent's models alive will more than likely result in a tie) but really how often does it happen? Every game? Every one in five? If it happens a lot then either there's no terrain whatsoever or your opponents are making a lot of mistakes often. It's hard to come back from massive out-activation yes, especially when the Viks have Whirlwind'ed any model that's vaguely threatening from the table early game but, even if it's the most flukeiest luckiest set of circumstances ever, you could still win with nothing more than Wk4 significant models. Without living in a dream world though, facing down perfectly positioned death squadrons is tough without knowing exact threat ranges and a small amount of card counting, thus why Perdita, Levi, Sonnia, Viktorias are normally met with an audible "ehh" from new to advanced players.
On further musing, in my meta at least, the same "oh jeez, really?" can also be said about Dreamer, Collodi, Colette and Jack Daw. Masters and core crews that don't strictly rely on murder but still absolutely mess with your models to the point of stasis.
Jack Daw for instance isn't what you would call a damage dealing god, but being able to (effectively) shut down 3 models with basic ease, he doesn't need to be. He doesn't kill your models, more he gives your models the opportunity to kill themselves. With so much control on the board, your models don't have to be dead to stop doing what they need to do in a game.
Collette isn't killing any master but with enough experience playing Colette, she and her crew have free range of the table. Her showgirls and doves can pretty much be anywhere on the board and get out of trouble fairly well, interacting and placing scheme markers regardless of what's in their way. Hell, in emergency situations playing a purely thematic list, Prompt a Showgirl thrice, handing out 6 poison, then give the 8th posion and Siren Call them to A Sip of Wine. It's not perfect but it's an option (Or yaknow just Prompt Coryphee Duet a bunch and make me hate you).
It shows you just how much a mainly-support master can turn the tides when played well.
Thus I'm at an impasse, Killy masters can kill everything to win games, Support masters can tank that very same damage and win theirs. On the surface of things, Murder-makers have the upper-hand but looking deeper, I've found that it's simply not the case when looked at as a whole. Yes board wipes will win the game more often than not but getting to that point is a hard won battle if facing a support master with experience under their belt. Outside of not knowing the crew you're facing, a total party kill just doesn't happen that often.
From a new player perspective though, or even from the perspective of someone who has exclusively played killy masters until choosing to play a more control/support master, it may well seem to be that killing half the opposing crew seems the solution to all of life's problems. It's that clean-up duty that tweaks the details. A friend of mine has a fast support crew which typically runs up first turn to drop necessary markers, then second turn and beyond uses those models to tar-pit and drain Ap. They leave one or two models aside to gain Vp outside of combat with back-up summoning and the Slow condition being thrown everywhere. A Killy master still kills everything sure but can't always do that all important clean-up step to win the game when the dust settles.
So who wins out in the end? Both really. If you are pure kill-crazy, you lack ways to deal with Slow or Paralyze or an illusionary forest popping up. On the other hand, pure support only works for so long until you've gained board control but lack ways to do anything but deny some more. Solution? Have both. Joss in a Collete crew is synergistic well with her Prompt, whilst a Showgirl in a Ramos crew can get key models in very tough situations. Zen and Balance ladies and gentlemen.
Keep those cogs in your mind moving and have fun out there.