I'm trying out Mythic Game Master Emulator with Dungeon World. I've only done a few sessions of game setup but I'm already very impressed with the GME. I'd love to hear from you if you have thoughts or questions about solo roleplaying in general, Mythic in particular, or even just tabletop roleplaying in general.
I have both editions (1st and 2nd) of the Mythic GME, but I've only tried the first one. The second one (the one you linked) does look very promising though, and I know a lot of people have had very good results with the first one.
I'm legitimately quite impressed with it. It's very well written, and the system is simple enough to be rapidly applied effectively. It feels a lot like having someone to bounce ideas off of and occasionally surprise you. I'm also getting ready to run a game of Beam Saber with a couple of friends, using Mythic. Very excited to see how a "writer's room" approach to roleplaying will go.