Raul wrote:

when I change users computers or configuration they insist on the
configuration for outlook's autocomplete usage when they type an email
address.

Is this a good feature to copy from machine to machine? I always
avoid it in order to start clean and avoid issues like spyware,
cookies, etc.

The autocomplete feature is immune to "Spyware, cookies, etc.". It just
contains addresses to which the sender has previously sent mail. It's handy
to transfer when the user transfers. See this:
http://www.ingressor.com/autocompletetips.htm

will this feature work even if users go from POP to exchange
configuration?

Yes, but if the addresses in the cache point to Internet addresses and the
recipients have also been moved to Exchange, they won't do much good.
Better in that case to start fresh. If the recipients remain outside
addresses, the data in the cache is still valid.

What are the pros & cons of carrying over all of this baggage?

Pros: very handy. Cons: none I can imagine.
--
Brian Tillman