I really enjoy Sleuth Kings. The stories are interesting and the extra puzzles surrounding the Hunt for Isaac are really an extra treat. Sometimes the puzzles are a tad too challenging for me, but I can always fall back on the hint files if need be. At this point, I feel like I know Sullivan personally.
This is by far my favorite monthly mystery box. I love that there is a new mystery every month. The puzzles are challenging enough to be interesting, but not so hard I want to shake my head and walk away.
I've started playing with my sister across the country on FaceTime and we have a blast. I am absolutely addicted. Most fun I've had in a while.