I've been doing this for 7 years with great results and love the zero configuration needed for registering at any site with a unique email address.

In the past few months, however, I've been getting spam that simply brute-forces usernames across my entire domain, leading to hundreds and thousands of spam emails per day. Gmail catches all of it but this makes looking for the occasional false positive very difficult. I've lost a number of emails that ended up in my spam folder between pages and pages of real spam.