I chose fastmail because at the time it was very different from Hotmail as F/m had lots more features, but now I would say.
Reliability
Sieve script
Excellent virus protection
Not much junk mail
We can host our own domain
It's fast
Support
But sadly most links and buttons are stuck in the left hand corner.
It lacks in a good user interfaces, really there is no choice of colors or smilies.
There are lots of things missing in the current UI that are in the classic....I would like to ask....WHY
Sorry but I'm not buying it if half the bits are missing....