Does the latest WP version have the 'MU-plugin' functionality?

Hi, I have WP MU 3.2.1 and BP 1.5. Reviewing your manuals, I’ve known about the mu-plugins:

Is this concept working in the last version of WP (3.2.1)?

In my case, I need that new user-created sites look the same and have a set of plugins activated by default. What should I do?

(a) use the mu-plugin functionality, or

(b) use resources like these:

Thank you!