Comparisons and advocacy

You can install Moodle on a server in about 10 minutes. Then you will want to do some customization (Choose a theme, turn off or on site wide blogging/messaging, etc.).

If the course is fully online and run mostly unmoderated, most instructional designers would say 10 hours of development per 1 hour of user time.

As for users, are they using an LMS currently? What sorts of courses will they be taking? In general Moodle is a great fit for any circumstance where you need folks to learn something.

Features
http://docs.moodle.org/en/Features

Plugins for additional functionality
http://moodle.org/mod/data/view.php?id=6009

> how long from start to finish will the installation take?
There are service providers who offer "1 click" installation, say you have Moodle running in 10 Sec. Then there are others who try and give up. So the time varies from 10 sec to infinity.

> Will Moodle be an appropriate choice for 3,000 users regarding the time necessary to acquaint users with the system and
The users will do it right if they are properly guided.

> set the appropropriate administrative restrictions?
Will depend on what is "appropriate".

> If we are developing a new course, have users found course development to be a seamless process?
You mean the course developers. Provided they have developed the course independent of Moodle, changing the medium to Moodle is not a big thing, if there is an onsite advisor who is knows the ways of Moodle.

> How long would it take, on average, for a basic course to be developed?
As mentioned above, the course must exist _before_ Moodle.

> Can someone list the basic functions and capabilities included in the newest downloadable version (1.9.9)?
Why basic? Get a good book on Moodle and you have all the core functions!