I just played a couple games of Coldsnap Sealed. It's...eh...I don't really like it that much as a Sealed format. I mean I tried this green deck and I lost (in one game I got a triple Surging Might, but my opponent had Surging AEther and wrecked me, so that was sad). And I tried this white-blue deck and won the first game, lost the second game, won a really close third game--I sideboarded into a BR aggro deck because my clock was low and I had to win fast, so I played a T2 Goblin Furrier and my opponent played a T2 Sheltering Ancient, and he kept putting counters on my Furrier and trying to play snow creatures to block it, but I kept killing his snow creatures and getting in, and eventually I just barely won the race with him at a few seconds on the clock. It was intense.
That being said, it's pretty disappointing opening a Sealed pool and never getting any sweet multiples. Draft is better because you can try to be the guy who has the deck with 12 Surging Dementia and be like, "Turn 2, land, you discard six cards, go." Or at least I assume it's better. I've never played a Coldsnap draft. I'm in an 8-man queue right now, but it's not firing so far. Been waiting for like an hour and there's only three people.