[x0]

Not if you have more than five subdomains, you have to wait for a week, like me.

[detaro]

... if you need a different certificate for each subdomain. You are limited to 5 certificates per domain per week, each of which can be valid for many subdomains. Bad if you want to be able to add them dynamically every time a new name comes up, but if it is a static set...

[mitchty]

I used SubjectAltNames on my setup. One domain/one cert, though I only did 2 subdomains.