Set-Up TimeAll three games mentioned here take a little bit of time getting minis, board sections, and decks out of the box and set up to play. Many of the dungeon-crawls that went before them put all the set-up and prep work on one player, who was GMing or at least playing the villains, but these three new games upend that paradigm. You're all working together, and there's no secret map that only one player can access. Assuming someone at the table has read the rulebook, and you've all played a good demo that answered the major questions, how much time and effort does it really take to set up when playing for your second time?
The short set-up time is one of Myth's strong suits, especially when compared with the standard for these sorts of big-box dungeon-crawls. With Myth, you have the ability to start play almost instantly (as long as you already know the rules, which is far from guaranteed with Myth) via the “free questing” mode. Free-questing, which is my preferred play mode, starts with any single terrain tile and drawing any one quest card to go with it. You dive right in and are playing within seconds. The Slaughterfield game mode is also immediate action with no delays, starting a few seconds faster than free-questing. Only Story Mode requires any set-up at all, and even then it's pretty fast and simple due to the nature of the game components and the very simple diagrams in the rulebook.
Galaxy Defenders takes a lot of set up, including custom-building the close encounter deck, building/stacking the event deck, and laying out complicated and precise arrangements of lots of little 2x1 terrain objects according to a map image that has to be carefully referenced before play can begin. This takes a lot more time and attention than even the most complicated story-mode scenario in Myth. GD's set up is actually kind of a burden. Getting something wrong in the board or deck set up can really mess up the scenario. The game works well, and all this prep allows the scenarios to offer quite a variety of play experiences, but you certainly need to budget set-up time into your plans for the night.
From what I can tell, Shadows of Brimstone will fall somewhere in between, but much closer to Myth than to Galaxy Defenders. The one game of it I've played had a lot less rigid scenario structure than GD. SoB uses card draws to build the map as you go (somewhat like Myth but with randomness instead of player choice) and you always start on the same entrance tile. That's all pretty speedy. Our mission had an end goal to reach, which was triggered by revealing exploration tokens (one of which is drawn with every new tile). This seemed quick and random, but it's unclear to me if individual sessions require any amount of customizing to the pool of exploration tokens, or if there are other missions that get more complicated. Character creation and leveling-up are both much more involved in SoB than their equivalents in Myth, and I suspect that will result in a slower start to the actual play of each session. Choosing new powers and spending in-game currency will take at least a couple minutes before you get to head into the mines to adventure.
And The Winner is: To whatever extent there can be a 'winner' of the "Set-Up Time" comparison, it's definitely Myth. The game is structured to have as few delays and as little down-time as is humanly possible.