I do all my tagging and 'management' in MB. I use MB to listen to my music when I'm in the house. And while there is a SubSonic plugin, it hasn't been working well for quite some time and the author seems to come and go, without making any substantial improvements.
I don't care about play counts, so I can't comment with full knowledge, but just doing a google search it appears that the SubSonic developer recently added the ability to get play counts via the API. You would need to figure out how to get it to interact with MB. It does seem to respect ReplalyGain.
You can download and use SS for free (with its web interface) and try it out. You'll need to install it on a machine that's running 24/7 that acts as its server. It will play your media on DLNA devices.
I suggest you visit the website and read through it all to see if it will do what you want.