@Steve Wilkinson - It's more than just core updates in consideration. WP Engine does not allow automatic plugin or theme updates yet, so it is indeed much more restricted. Certainly for those who feel they need the safety this is a good measure. But for those who want to live on the edge and make use of everything 3.7 has to offer, you won't find those freedoms with a manged host. They restrict features native to WordPress so they can perform them for you instead.