As far as using MC over a network. This works great and you really won't have too many performance problems, as long as you get reliable network equipment. There are a few things you need to know though...
Mapping Network Drives...The way it works is you can "share" the contents of a folder on one of your computers with the network. This is quite easy using Windows XP Professional (and Home too though home edition is slightly less capable).
Here's a good article from Microsoft on how to do it. And
here's an article about "Simple File Sharing" (XP Home's way and Pro's default). I much prefer Non-simple file sharing. I actually find it much "simpler".
Some routers now have this capability "built-in". So, instead of sharing the contents of a drive on one of your computers with the other computers on the network, you can simply put the files you want to share on a drive connected to the router. Other, similar, solutions are to buy standalone NAS (Network Attached Storage) devices that do effectively the same thing. Generally these work okay, but aren't quite as featureful as using an actual computer to "serve" the files. The one nice thing is that you don't have to worry about setting up and configuring a computer to "serve" the files (and you don't need to have XP Pro to use the better "non-simple" sharing methods).
When you want to use these shared files on your other computers, the simplest way is via a Mapped Network Drive. Essentially all this means is you tell windows: "This shared folder on the computer called FileSharingMachine? I want you to automatically connect to that share all the time and call it drive M on my computer."
Here's a tutorial from Microsoft.So, when using this with MC, the easiest thing to do is to put ALL of your media all in one "folder" (you can divide it up into subfolders of course) on a computer (or a NAS or one of the fancy router-drives). Then, map that folder as
the same drive letter on all your machines (including the one where the media lives). So, for example, my setup is like this:
1. All my media (or at least most of it) lives on a RAID5 volume that lives inside my HTPC. (It used to be in my Linux box and it will be again but for now it's in my HTPC.) That drive is called Drive M (for "media") in Windows on my HTPC. I selected the drive and shared it (right-click on the drive icon in Windows Explorer, choose sharing, click "New Share" and give it a Share Name).
2. All my other machines in the house are connected to the network (mine's wired but wireless would work as well -- certainly perfectly well for music). On each of those machines, I mapped the media shared folder on my HTPC to Drive M. That way they all match! When MC's library points to the file at "M:\music\Bright Eyes\I'm Wide Awake, It's Morning\07 - Another Travelin' Song.mp3" that file is there and at the same place on any of my machines, since they're all mapped to drive M, so it works on all the computers!
MC's Library...As far as using MC, there are a few options about how to handle the library files themselves. The performance things you heard about generally aren't regarding having your media files themselves on a network drive, but mostly regarding the database files (MC's library). The way I do it is I have each computer's MC have it's own "copy" of the library on their individual C drives, and then I have a few scripts that use the HTPC's copy of the library as the "master" and automatically updates the library files (overwrites them) on the other machines once or twice per day. Since the library all points to the files on Drive M on the HTPC, and all the other computers can also "see" the same files on Drive M, it works fine.
Playing files back over the network works fine (with a wireless system you might have some trouble with big video files, but I've even done this without trouble with a high-quality 802.11g router). If you do any "management" of files on the "network" machines (such as rename files from properties or whatever) that will be much slower, but it still works. I've found MC12 is much better behaved with network files than MC11.1 was.
The other option is to just put the library files themselves on Drive M and have all the copies of MC use the same library files. This is a new capability of MC12. When I did this with MC10 and MC11, there were all kinds of performance problems. You also ran the risk of damaging your library (if two computers tried to update it at the same time it could become corrupted). The way MC12 works is the first computer that "opens MC" becomes "in charge" and can make changes to the library. Any subsequent copies of MC that open (while the first copy is still running) can still use the library, but can only open it "read-only", so all tagging is completely disabled on those machines.
I have not tried this because my system works well. I don't know if they've solved the performance problems I saw before when trying a similar system myself with MC10 and 11 (MC would freeze up periodically when playing back with an "updating database" message).
I suppose a third option is to just have each copy of MC maintain it's own separate library and keep all the tags stored in the files, and just let Otto keep them in sync. This would only work if all your file types support all the tags you use. I use video a lot (and MC doesn't save tags inside AVIs or most other video file types) so this isn't an option for me.
There are lots of threads about this stuff here, but if you want to set up a system like mine (with each system having their own library, but having them automatically "synced"), you can use my scripts which I posted over here:
http://yabb.jriver.com/interact/index.php?topic=35978.0