I have used MM for almost 4 years now since the WMP(vista) I had used for 7years RESET and lost ALL my library data statistics whence I reached a bit over 70k+ tracks. Upon searching for new player Found that MM could handle MORE library items (reached about 142k before the Vista motherboard static short-circuit blewout. I lost all of the generated statistics, etc. (do not yet know how to SAVE the generated stats,playlists to import to new PC...?) and was in the 3rd iteration of highly-structured library architecture when my new Win10 system that I have had for 14 months actually caught on FIRE (big flame in formfactor) at the storage HDD power input and melted it thus destroying over 700GB of hi-quality MP3 files I had developed and tweaked for many,many years. In the 4th iteration I am contemplating re-creating all files lost into the FLAC format (since storage is much less costly than 10-15 years ago and will likely need 20+TB to house the audio library with new archived items) I have not yet attempted to extract audio from CDs with the MM player with FLAC settings but I know I had just as much headache with MP3 320bitRate as I had with WMP on Win10 with rips taking over 10 minutes on FAR Too Many disks new and used. (WMP in Vista NEVER had a problem taking longer than 3 minutes to rip unless disk was actually defective and I have no idea to this day what is going on what is wrong?)
A few things I have liked using MM:
1.adding Hi-Res albumart that auto-sizes as you adjust size of albumart view window (WMP never allowed this in Vista so had to stick with 600~800px images to fit in the window...WMP in 7 and 10 did away with this view...total jank)
2.The ability to have media library with MORE than 70k items AND ability to randomly play ALL of them. WMP only allow 20k items to randomly play from various library view even though library consist of more...total jank again. To get all tracks to play randomly you have to sort filter and select all tracks and not just double-tick on one as you can in MM
3.Specific time-stamps with date added filter. WMP only grouped albums with a particular hour whence add and then arranged in alphabetical order. MM allows for much-improved date-added feature when you need a concise and coherent library structure. ThankYou MM

A number of things I do not like or find troubling using MM:
1.Not able to open 'containing folder' from the right-tick button as I can do in WMP ... any way I can do this that I have not discovered yet? always having to goto ThisPC-driveLetter-folder-folder-folder-folder when needed is heavily cumbersome
2.Not able to edit properties in main library view using the arrow down key as I can in WMP. i.e., most tracks with multiple or featured artists show up with the ;semicolon; separator and I prefer to change this to 'artist featuring artist' as an example. When I use the arrow down key to do next on list it always comes up with an 'auto-fill' of various whatever instead of just going to the next track for editing as it down in WMP. Always having to double-tick mouse on every track to edit individually is heavily cumbersome...are there any shortcuts I have not yet found to do this task?
3.When playing volume at lower levels the sound from the rear surround speakers is Horrific and distorted...In the WMP I used the SRS WOW filter to compensate and make a more pleasant surround sound experience. In almost 4 years of MM experience I have yet to find the right tool to fix this problem. I have tried an add-on or 2 but they just don't seem to work as intended or perhaps I don't set it up correctly? ... heck, maybe it is the Hi-Quality MP3 files in use that is the culprit and the FLAC format will do away with the low-level distortions?? … I have yet to do the blind-audio test FLAC vs MP320 and see what difference, if any, there is.
4.Not being able to drag and drop a folder with files into the main library view and have it added in track order as it does in the WMP. Is there a way to do this with MM that I have not yet figured out? ... The way I add tracks now is to open the containing folder, sort ALL tracks by track number filter (not alphabetical as is default in my view) then select all and drag with mouse way across to other monitor into the upper left corner of MM to the proper place to add files ... I am not sure Why I am not able to just drag and drop into the main window view of MM as I can in WMP? any clues as to why not?
5.The statistical filter I most use (besides play count) is the date added. In WMP I also used the 'date-created' filter as not all tracks from some albums are added to library at same time it was created. i.e., one genre I use I have 'random play addon days' a couple times per month, I then add to library when they are played for first time from containing folders. I have not found a 'date created' filter to sort in MM, just a date modified which is not of much use as it is variable and NOT static as 'date created' is. Maybe it is somewhere in options that I cannot see?
I likey have a few more Likes/Dislikes over the past many years but I have spent enough quality time on this post
Over the years I have investigated some other media players (Foobar, JRiver to name a couple) but neither of those could I figure out how to display the intricate statistics features available and offered in MM.