I'm a long-term user of MyMovies and following Jamie's suggestion on the MM forum I've had a first look at the software.
It looks very good (and it doesn't have the issue I have at the moment with MPC-BE when launching some titles from MCE), so well done. It looks like it's not far from being the MCE replacement that I could use as a front-end for MyMovies (I don't like any of the other front-ends I tried). I have jRiver as a standalone/don't need MCE/play UHD BD Menus solutions, but I still use MCE/MyMovies due to some features that I haven't found anywhere else.
I've run in a few issues though and I have some questions:
1) Filters and categories do not seem to work. I get the following error whenever I try to access these:
Categories are one of the main reasons why I still use MCE/MyMovies, as jRiver handles tags but doesn't support the MyMovies categories. I have 3,000 titles and I don't really want to retag all my titles

2) MyMovies supports WOL, so that when a NAS is powered off, it sends a WOL magic packet to wake it up if I try to play a title that's not online. I don't think CMC supports this. Any chance to see this added?
3) MyMovies supports Vera Lite automation, and I use this to switch the lights off when playing a film, and switch them back on when playback stops. I haven't seen any mention of this, so is it something that you might consider adding?
4) I've looked at episode supports for TV Series in CMC and it's too clunky fro my taste. I have more than 6,000 points in MyMovies. Any chance to see the MyMovies API supported so that we get direct episode playback support, as in MyMovies, from bluray and UHD Bluray discs once the episodes are mapped in CM?
These are the main showstoppers at this stage for me. 1) and 4) are the most important. 2) and 3) could wait, but I wouldn't commit to the software unless I knew they were on the roadmap short term (happy to help with beta testing by the way).
I still have a working MCE install, although I have to use MPC-HC rather than MPC-BE due to recent issues. So at the moment, I use jRiver when I need UHD BD Menus, and MyMovies/MCE for everything else.
Looking forward to hearing your thoughts, and again well done for a very nicely designed software.