I have used mu for about month now. We have hosted about 175 blogs for our clients. They are each on a subdomain off of a common master domain. Here is
a summary of my experience so far:
1. Installation was simple! this was the easiest part.
2. Things worked pretty much like you would expect - no real problems.
3. I have a few questions about "primary" and "secondary" blogs, but other than that, everything seems straightforward.
4. I added some functions to the xmlrpc module so we could do alot of configuring remotely, via a batch process. This has worked like a champ.
So here is what I would say, when comparing mu to lunabyte's famous hack:
1. There is a nice interface for handling the multiple blogs. There is a concept of an admin "superuser" who can go in and modify any of the blogs, without having to be a user of a paricular blog. This, IMHO, is the nicest feature of mu.
2. The concept of "user" is not tied to a particular blog - if this is important to you, it is nice (for us, it is of no consequence, as each blog is a world onto itself, and users wouldn't really be in common).
3. If you so desire, there exists the facility for allowing anyone to sign up and create a blog, and also to delete their blog. Again, for us, we do not want this feature - folks pay for their blogs from us, and we set them all up with a specific configuration.
So, the real issue which we haven't addressed yet, is that of allowing each blog in an mu farm to be assigned an (additional and optional) arbitrary domain, and to allow arbitrary deep-linking from that domain. That is, if in
the mu farm, a blog is:
blog1.farm.net
but we want to use a domain like "mydomain1.com",
we would be able to do allow linking from outside pages like:
http://mydomain1.com/2008/01/01/my-article
(in addition to http://blog1.farm.net/2008/01/01/my-article, which works already).
It seems like it is easy to access a mu blog via an external domain using a standard "forward". For example, in godaddy, you can forward the domain "mydomain1.com" to "blog1.farm.net". If someone types "mydomain1.com" in a browser, they will get to your blog. Deeplinking even seems to work. However, at the top of the browser it will not say "mydomain1.com", but rather blog1.farm.net". That is, once you get to the blog, all addressing is "native" (not rewritten). If that's not a problem, without further hacks or work, mu does the trick.
(BTW, I am working on a plugin for mu to allow each user to efficiently access their site stats from awstats through the admin interface. If anyone is interested in this, please let me know)