Looks like WPEngine is migrating away from Linode… I'm both a Linode and WPEngine Customer (Have two sites with them) and got notices today that IP's had changed for both all now Rackspace Cloud.
Pretty interesting since I think Rackspace might cost them more
It's not always about the price or the quality of service, sometimes you need need some feature that one provider doesn't offer. Object storage is an example of a "cloud" feature that Linode is missing that all their larger competitors (AWS, Azure, RackSpace) have, for example.