I'm also always actively looking, and they look interesting, but their recent blog posts don't fill me with too much confidence (although they have to be commended on being so open about it). Any personal experience there?
I used to run my own mail server for years but spam was becomming a problem as it always does when running your own system and I thought the pricing of most of the services was poor if you had lots of addresses but didn't send/receive many emails. Spam hasn't been an issue for me with mxroute so far and their infrastructure seems to be pretty solid.