Wordpress Multi Sites - Pro's and Con's. What are it's limits?

[Whitey]

I'm having some sites built with Wordpress, and the developers who specialize in WP recommend not to use the multi sites version. They say there are issues beyond a certain point of scale. They didn't elaborate even though I could have asked.

How far do folks think you can take multi-sites; and what sort of limitation can you see; what's been the experience out there ? What's it good for, and not good for ?

[lorax]

I'd sure like to know what limitations he's speaking about. WordPress.com is built on a WordPress network and it runs quite fine. The only issues I think you might run into have to more with limitations of your host or poorly written code.