Just started this the other day and have been playing it Very Much since then.
I had the most luck getting my first wins with Awakened main and others supporting, especially once I unlocked the exiled champion and started using him instead (though I've unlocked a few more spine-related cards since then, might be worth a try again). Though growing thorn-wardens with a bagillion health was always a lot of fun.
Hellhorned are
fine but I feel like they're better as supporters, since they're pretty straightforward. Like, the armor stuff is pretty cool, but still pretty plain? Stygian doesn't do much for me - it feels like it's too finnicky to get their good combos going consistently, or something, though I do love Sweeping enemies with Frostbite. The Wurmkin are neat but I feel like their special resource is juuust a bit too scarce for all the demands that consume it (like eggs).
The Umbra quickly became my favorites once I unlocked them, so I followed up by racking up wins with them. What can I say, feeding morsels to my crew and watching them grow crazy strong was Very Good. I also liked that they had a lot of extra sources for ember generation, which I always greatly appreciated, and made up pretty well for needing the space-expanders after bosses. I definitely preferred the main champion to the alternate; it just doesn't seem as useful at first glance although I'm sure there's some specific build or trick that makes it even stronger.
Then I unlocked Them Waxy Boys just last night or this morning, and
they quickly overtook the Umbra to become my favorites. Letting my dudes get ground up and just bringing them back stronger than ever was immensely satisfying, not to mention powerful and strategically flexible, especially combined with the hellhorns' strong-but-low-defense guys (and Inferno, though I didn't get to use it
) . I just ignored extra armor stuff and suddenly every level was packed with very strong boys. In fact, I lost my last run only because I overpacked some of my floors and didn't have room to bring back my resurrected boys as the boss moved up, leaving weaker ones filling space. I also need to figure out balancing Reform and Endless - a couple times I'd forget and a boy I played with the intent of getting him reformed came back Endless instead, without the extra strength. Especially since I had the (otherwise amazing) trinket where my first boy played on each turn gets endless. Feeling out when I want a card back the very next turn and when I want it to get stronger instead (also, the timing of how reform works with burnout and deaths) is next on my list.