Opened Gideon of the Trials, Invocation Vindicate, Temmet, the UW cycle land, the new Hero's Downfall in my pool. Went WB with a splash for Temmet and the 2UW embalm bird that gives tokens vigilance and flying off the cycle land, an island, and evolving wilds. Went 2-0-2 with the last games of the drawn games clearly in the bag. I didn't want to be a jerk, but I knew from the moment we ended the first game of the first match, it was a draw. My opponent generally took forever to play, had multiple 1 minute plus turns where he literally did nothing, forgot draw steps only to take them back at the end of his turn, sideboarded, did a full pile shuffle, then thought he forgot something in sideboarding so he did it again, AND took a couple minutes to fold his jacket into its own pocket instead of just hanging it on the chair. I watched the clock pretty intently and 100% guaranteed used less than 7 minutes of it across all three games in my priority.
Similarly, I was beating down my third round opponent handily- had him 31 to 2 with an unblockable 2/2 lifelink on the board in turns when it ended, among other things- but he also played slowly, though not as much as the first guy. Was frustrating that round because I asked if he was done nearing the end of time, he said no, thought about it for 2 minutes, then time in round got called and he passed to me after getting round 0 declared on his turn without doing anything. I would have won with that one more turn had he passed sooner.
I recognize that prereleases bring in new players, and even the vets that come in aren't necessarily efficient tourney players/know the new cards. It's also a non competitive event and I already had absurd value in my pool from the invocation and Gideon, so I didn't press it, but those were two matches I would have 100% had in the bag on mtgo (nice to praise mtgo for something it actually does better than the in person game every now and then!) so its super frustrating to lose prizes to that, especially given the frankly almost shady actions. :/
Prize pack had a harsh mentor, though, to top off my already great pulls, so all in all, a good experience. I think the format is fairly fun on first glance, but definitely prone to ground stalls as others have noted.
Highlights of the day were Sacred Cat tokens doing roughly a billion damage across matches thanks to Temmet, and being the bad guy who color screwed his sealed opponent on turn 3 by vindicating his only island.