MultiSite Pros & Cons

I just realized the plugin I wanted most only works with Multi-Site install (the support plugin).

I know nothing about Multi-Site (yet).

I’m running 5 WordPress blogs.

For those who have used Multi-Site and single installs, is it going to be in my best interest to upgrade now? (And take the time to learn the system, and convert everything over?)

What’s the pros and cons I need to consider?

Is anything going to not work on the Multi-Site install that works currently on the single site install?

Lastly, will I be able to develop locally on a MAMP server using wordpress Multi-Site?

Sorry for the total newbie questions. I’d rather just get some specific answers now before investing hours only to find Multi-Site isn’t going to cut it for my needs.