FBSD jail versus VMWare? What services do YOU run in a jail?

[edflecko .]

I'm really interested in the comparison of using a FBSD jail rather than
VMWare in the context of virtualization.

At my business, we heavily use VMWare - you might say we consider ourselves
a VMWare "shop". 99% of our servers are virtualized.

I've heard that it's possible to run hundreds, if not thousands, of
services in FBSD jails on a given host server because of the sharing of
resources that all of your jails take advantage of. If I understand that
correctly, that's one of the HUGE advantages of running services in jails
as opposed to creating VM after VM after VM - each VM eats up disk space on
the SAN as well as memory resources, etc. Additionally, the jailed service
is far better from a security perspective?

Having said all of that, I'm curious to hear from some of you who may be
doing just this - are you running a FBSD server with some of your mission
critical services (Apache, Bind, DHCP, etc., etc.) within jails and how do
you like it versus running hundreds of VMs and VMWare?

What type of services CAN be run from within a jail?

Thank you,
Ed