Its been a while since I heard either but based on my prior experience, I would take the Val2 over the Crack any day. Val 2 gets tonality down for starters and has better bass extension than the Crack, though maybe the Crack is sweeter/more euphonic sounding.

loving the hell out of the valhalla 

Vali does take a hit in resolution but also picks up a couple of presentation characteristics that can be nice.  I keep all three stacked on my desk:  Vali/Magni 2/Wyrd.

Been listening to the Vali for a day, it's pretty nice piece of gear for the price. You do lose a bit of detail, but it's not a dealbreaker (especially at $120), and you do gain a bit of the "tube wetness" characteristics that people are after. The bass is rounder and the mids are lush with a smoother top end. Even though the highs are smoother on the Vali (compared to like the Magni2) it still does occasionally have issues with hardness in the treble (byproduct of it being hybrid?). In a zombie apocalypse I could live happily with this as my only amp.

Compared to a decked-out Crack (Speedball, TS 5887 ($90), Telefunken 12AU7 ($60)), the Crack does seem to edge it out in terms of detail and speed, and still maintain a lush midrange, impactful bass, "textured" notes. Keep in mind though this will cost you over $520 and you have to build the Crack yourself. A Crack without upgraded tubes (RCA 6AS7G, E-H 12AU7) is more in line with the Vali, but more tubey sounding ("euphonic", thick midrange, round bass) and might even lose out on speed.

Nice thing about the Vali is that it plays nicer with a range of impedances, the Crack being OTL plays best with higher ohm headphones. Overall the Vali is a nice "gateway-amp" into the world of tubes. Captures a small essence of what tubes can offer and makes you wonder how much better it can get.. "down the rabbit hole" ala Lewis Carroll. A great first tube-amp purchase for those curious, but you've been forewarned, this probably won't be your last tube-amp (Spoiler: It can and does get better).