1) yes - xampp is an example of an amp stack for windows
2) better handling of larger lists (and more efficient processing), automated "bounce" NDR list cleaning, can be set to use a different IP address from your "normal" email services so as to lessen the odds of your mail server being listed as a spam source, and (if you choose to make it web facing) ability for users to sign up and resign from a mailing list themselves using a web gui.
one key thing to remember is that when ms word mailmerges to email, it has the entire resulting "document" in memory, all at once. for a large list, that can be quite a large document, and hence can drag down the merging pc quite a bit.
