I just finished running this for a group of four players. Having read the whole thing beforehand (I got to the bit where it suggests having a rotating GM and thought "pull the other one, mate"), there were already a few problem areas jumping out. Actually running through the thing shone an unflattering light on what I consider Alas Vegas' biggest flaws, but also highlighted some surprising strengths. My overall thoughts are that it's kind of a railroady mess, but brings some interesting ideas to the table. If you've got a GM who's willing to jury-rig its components into an actual campaign, and a player group willing to buy into the premise, then it might be worth a look.

Unfortunately, as an actual adventure Alas Vegas is pretty weak, and after some reflection I think most of its problems stem from its insistence on having a rotating GM. It's a fun gimmick, and if you've got a group of friends who'd be game for it I think it's something that could work with a different system. I don't think Alas Vegas is that system. With everything it tries to do, the things required to make it work, and the way it drip-feeds information, I think it'd take a really talented group of GMs to actually make something enjoyable out of the rotation. So, I guess if you're a skilled GM who's friends with three Matt Mercers, give it a shot? I ran this as the only GM.

This adherance to being able to be run by a rotating GM has pretty dire consequences for the adventure. Each session has one or two key beats, a smattering of exposition, and then a lot of scenes that are generally a) boring and b) have predetermined outcomes the players have no control over. Several times the GM is given no instructions on how to run a particular conflict, instead being told "here's the Deus Ex Machina to pull out when you think it's time for the next thing to happen". And that really is the core of Vegas. Go here. Talk to this person. Now it's time for the next thing to happen. Very little the players can do actually affects the outcome of anything - short of refusing a fetch quest or not playing nice with the NPCs, players have very little agency (and the book repeatedly insults players who do try and break out of the railroad). For any other adventure, this would be a glaring flaw. But for Vegas, with its rotating GMs, it becomes a necessity. Nothing the players do matters, because it can't matter if the session needs to end at a predictable place for the next GM to pick up. It's a linear, railroady mess, but it has to be for the rotating-GM gimmick to have any hope of working.

It probably sounds like I'm being a little harsh on Alas Vegas. To its credit, I did enjoy running it a lot! The way Flashbacks work is a fun piece of collaborative storytelling with your players, and it's woven into the game and the story both in a way that's very satisfying (what people who like long words would call ludonarrative assonance, I suppose). Vegas' setting is very fun, and while its twists and reveals aren't that surprising they also aren't strung out for too long. Four sessions feels like exactly the right amount of time for Vegas; my group ended up stretching it out to five, because it took two sessions to get through one act before I realised I needed to start cutting a lot of stuff out to get through the sessions in the 3-4hr time span we had each week. (Luckily, as described above, there's a lot of useless bloat that you can throw out of any given session to streamline it. Unfortunately, if you're doing the rotating-GM thing you can't skip stuff as easily because you don't have the foresight to know what scenes will actually turn out to be important and which are just dead ends.) Four sessions is enough that the final scene (which is extremely good, easily the highlight of the campaign) has satisfying buildup, and also mercifully terminates the campaign before the mystery starts to become too drawn-out and the lightweight system starts running too thin.

If you want to play Vegas exactly as it's laid out in the book, I can't really recommend that. The adventure as written is kind of broken, and rotating GMs is a gimmick that seems fun on paper but, I would imagine, is a chaotic disaster in practice. However, if you're willing to slice the adventure open, pore through its innards, and reconstitute the best bits into something new, there's definitely some moments of brilliance in among the slurry of poor adventure design. I've seen it described as "like playing through an HBO miniseries", and honestly, that (and everything it implies) kind of sums it up. If you want to read more about the setting/content, there's a great write-up archived here; it's got spoilers, but is also the thing that sold me on picking up and running the adventure. Overall, if it's the kind of thing you think you might be interested in, I'd probably recommend picking it up; even if as-is it's a little wonky, there's bound to be something in there you'll get use out of. If you're looking for a more traditional adventure... probably give this one a miss.