Helpful tip, this is the first time I heard of this version of WordPress. Downloading and installing now. -D
If you have a pool of writers, and have no financial problem I would recommend you to go with individual domain for each nichie. In that case you may also sell one of your domain/site/blog in a bad time(if you ever need money badly). Beside that each domain with it's own pr will be a high value as compare to one domain with several pr associated to it's subdomains.