I signed up for Fastmail before doing a bit of travelin around SE asia mostly because I didn't want to have to put loads of numbers after my name to get it as an email addy.
I didn't realise how fast it was until I was sitting in a cyber cafe in Hanoi next to someone I'd meet on a bus by the time they'd got the login screen on Hotmail up I'd already read my first email this difference in speed was a regular occurence whereever I went
I don't know or care why Fastmail is as fast as it is, I just sit back Smug in the knoledge my Email provider is brilliant .