true...i think both have built encryption options....but i also like the idea of people not knowing my identity when i send an email, unlimited disposable address, and my own domain email.
So do you want email content privacy, or do you want anonymity. the privacy of content is much easier through encryption the anonymity is also easy if you only want to be anonymous to the recipient (even hotmail don't send the opriginating IP in email headers like they used to but your IP will be known by them), if you want to be anonymous to the likes of governments, you will have to Tor or VPN daisy chaining.
For unlimited disposable addresses then use guerilla mail or some similar 30 minute mail box type service.
If you want your own domain email then you don't really get anonymity, I have many domain emails because I own the domains, some domain seller let you set email forwarders for free after purchase of the domain name without hosting. (daily.co.uk), If you own the domain though you will have a whois record with your info on or where you bought it from will know your card details / bitcoin address / IP address etc. but with your own domain email you can have
anything1@yourdomain.com anything2@yourdomain... etc etc I'm sure you know this already.
Anyway the above poster made good suggestions on email providers and pgp.
P.S have you seen the latest Snowden interview, he details the NSA ?keystone? system that allows them to track anyone over pretty much all digital coms, the capabilities he describes are awesome and awesomely scary.