By “burnt to a crisp”, I mean that mediamonkey bogs down after about 60K tracks or so. By bogs down, I mean it takes multiple seconds per keypress when searching for tracks or artists or what-have-you. this is the same issue with iTunes. No system I know of can handle the large amount of metadata that is generated by having so many tracks.
For now, I have split my library into 5 chunks with mt-daapd and that has acceptable performance in iTunes.
I *do* really like MediaMonkey for tagging, etc., and I continue to keep it around.