WP Engine is awesome. I have a number of sites hosted with them. Super fast, easy backup/restore, staging area to play with changes, and fantastic support. Hosting is definitely an area where you tend to get what you pay for. If you have a site that you really care about or that you’re trying to actually make money with, then WP Engine is a no-brainer and absolutely worth it.
Support is probably the feature that will make the biggest difference in your hosting experience. When you need help with your site, you want to talk to tech-savvy people who can solve your technical issues quickly, and are patient to help you figure things out. Since you're hosting on WordPress, make sure the support team is comprised of WordPress experts, so they can fix not just the servers, but the site as well.