Below, I shed light on the results.

Test games
First, I played a couple of test rounds with each deck and recorded the outcome and the time each round took to finish. Here's a list of the results (my deck, opponent's deck, time). Matches marked with green ended with a victory, the red ones, well, did not.

W - Warrior
S - Sorcerer
N - Necromancer
W - N, 1m 14s
W - W, 2m 26s
W - S, 0m 40s
W - W, 0m 43s
W - S, 3m 55s
W - W, 3m 35s
W - S, 1m 45s
W - N, 1m 14s
W - W, 2m 15s
W - S, 1m 05s
W - S, 0m 51s
W - N, 1m 41s
S - S, 2m 14s
S - W, 1m 21s
S - S, 1m 28s
S - S, 1m 34s
S - S, 0m 55s
S - S, 2m 40s
S - W, 1m 55s
S - W, 1m 28s
S - W, 1m 16s
S - N, 1m 18s
S - W, 2m 01s
S - W, 3m 13s
N - S, 1m 19s
N - N, 0m 48s
N - W, 1m 02s
N - S, 0m 29s
N - W, 0m 57s
N - S, 0m 36s
N - S, 1m 24s
N - N, 0m 41s
N - N, 1m 04s
N - W, 1m 04s
N - S, 1m 47s
N - S, 1m 10s
Conclusion
The warrior deck is a fine one and even though some rounds were relatively long-drawn, it's fun to play with it since it has proper attack, defense and healing cards. I'm not really into the sorcerer deck, though, because during my test games the main reason for losing was being stuck with 5 aura/node cards in hand, which aim to strengthen your attack cards, but I was barely dealt a couple of attack cards they could strengthen. Bad luck, I guess.

How to exploit the necromancer deck?
Playing as a necromancer is the best option, I reckon, becuase the 3 most powerful attack cards (Soul Crush, Blackout, Blood Boil) can all be found in this deck (see the game's manual for a list of all cards and their effects). Combined with the card "Soul Pile", which doubles the effect of the card that follows, they're a lethal weapon, no doubt. And although this deck contains merely 2 defense cards and 1 healing card, this is the only deck with drain health cards that not only restore the player's health but damage the opponent as well.
In the course of the game, I table the so-called "self-sacrificial" cards first except "Soul Crush"(Blood Chant, Fang, Sacrifice, Poison cloud, Blood Filch). These might drain the player's health even faster than the opponent's, but that's not a problem, for it's easy to regain it with drain health cards. Once your health goes below 20, table defense cards (Bone Wall, Blood Moat) or drain health cards. I generally table the "Heart Pile" card when my health is around 10 and I have no other defense/healing cards left. Use the aforementioned 3 powerful attack cards to deal the final blow. If you don't do so, the opponent might heal themselves and you wasted a rare card. If you're dealt such a card, keep it until you can defeat the opponent with it instantly. Just mind their defense markers. If you have a "Soul Pile" card in hand, keep it as well and use it along with one of the 3 attack cards for an epic final blow, unless the situation necessitates otherwise.
Use the other cards to taste.

Thank you for reading!
