Personally I'm a ST player, I'm not high ranked but I think my hidden MMR is around 3800-4000 based on the people I played vs in ranked at the end of last season.
Last season, my favourite deck was the Francesca Mulligan deck. Honestly, it was good fun! Had an answer to nearly everything, and could get that answer more reliably than other decks. I also dabbled with dwarves and spellatael, Dwarves I did enjoy with Eithne, spell I never really enjoyed (boring as shit).
Tried Stammeltael, obviously, the day it came out. Personally, I find that it's being massively overrated. For one thing, NR completely butchers the deck. It has really bad value in a situation where tremors doesn't kill anything.
Me personally though, I'm a ST player through and through. I'm now running what I consider a good counter deck to this deck, and it's actually working good so far. I've lost a few times with it, but honestly, that was mostly through misplays (and the first game I lost with it was because I still had Ithlinne in the deck, which wasn't that great). It's an Eithne dwarves deck.
Leader: Eithne
Golds: Saskia, Zoltan Chivay, Geralt: Igni, Vesemir (the one that gets an alchemy spell)
Silvers: Yarpen Zigrin, Barclay Els, Nature's Gift, Alzhur's Double Cross, Commander's Horn, Ida Emean
Bronze: Mahakam Marauder x3, Dwarven Agitator x2, Sage x3, Elven Merc x2, Thunderbolt Potion x3, Resilience Card x1 (forgot name, lol), Card that gives +2 to 6 random allies x1 (again, I forgot the name)
Not sure how competitive it is, remains to be seen. But it does seem to do good vs Stammel. The basic idea is to flood the board with Marauders, and go for a straight 2 rounds win (pass round 1 if losing and cannot gain advantage back). The amount of buffs you can do to the marauders is insane, and normally you end up with atleast 3 on the board. Stammel actually buffs the Marauders by one, and Weather is completely countered by them.
There is probably a few adjustments still to make. Not sure about the card that gives resilience yet, because resilience doesn't seem as strong. It's always great to start round 2 with a marauder or two though!