Hi maid,
You can accomplish the same thing using DLNA as you can with shared folders. I have exactly that setup. For years I have been using folder shares, but have recently moved over to DLNA in order to hook up MC15 to my PS3. The process is very similar, but there are advantages to DLNA. For one, MC15 uses a DLNA feature which puts up a screen shot of the opening scene of any video beside the item name. For watching TV episodes, that is very useful for picking where you are in the season. For another, when I hit one of the buttons on the PS3, it puts up one minute segments of the episode with a screen shot for each, and then as I move the selection box over the screen shots, they start to play in the little preview window. It is a very impressive feature which makes it super-easy to figure out exactly where you were in any video. It allows me to make them 1 min screen shots, 5 min, 10 min, etc. The videos also automatically bookmark, which is great. But if I had watched half of one on my downstairs computer, the screen shot approach lets me easily pick up where I left off upstairs in front of the TV.
There is no need to create any sort of login/access when using DLNA. I had previously created a special login and password for my upstairs device, then I had to ensure that my HTPC was appropriately sharing those folders to that particular made-up user. With DLNA, once you have it set up to share from the server end, any DLNA client can access it off of your network. That also means multiple DLNA clients can make use of it, such as iPods, DLNA-enabled TVs, PS3, 360, etc. No need to grant permission to each, if the server is on, the client will find it.
Probably the biggest advantage is conversion on the fly. I am serving to a PS3, which does not support all file types. So when I set up the PS3 profile in MC15, I can specify what format the file should be converted to and MC15 takes care of it. Essentially it means that any file type is playable on any device (although each MC15 beta update does make more changes in this area so I would encourage you to keep upgrading).
That's all I can think of.
DD.