has anyone made an all-Ruby website? how'd it go?

I run a website that's all PHP now, but was due for 
a total re-write anyway.  (The old code is a mess.)

It's more MVC style - where the code comes first and
outputs HTML from templates - NOT embedded code inside HTML.

I love Ruby so much that it's very tempting to write
my new version in Ruby (mod_ruby + Apache).

But I wonder if anyone who has already done a whole
interactive website in Ruby/modruby could share their
experience with it?

Were there any featured you really missed or any surprise
problems?   Would you recommend it for someone else?

I know the question is vague, but I can't tell if I'd
be making a big mistake by trying it this way, especially
if I didn't realize until I was a month into it.

Thanks!