WPEngine is smooth - but not that smooth

Over the last three months I've been developing a large site for WPEngine. The previous site was hosted on a simple VPS and the customer wanted a faster, more hands-off solution. I like WPEngine for a number of reasons:

• Hands-off caching
• Simple staging
• Simple backups
• Easy domain configuration
• Fast support

And so on. Finally, I thought, a service where you get what you pay for (and you do pay for it). And the site is fast. Really fast.

But the problems have started mounting. A quick preview of what I've seen just in the past week:

• Uploaded images occasionally disappear. I don't know where they go. The user who uploads them sees the images (they go into browser cache) but nobody else can see them. That makes this very difficult for an author to catch.
• You simply cannot set cookies from PHP. It will not happen. It will happen on your staging server, it will happen on your local server, but WPEngine's caching simply does not allow this. This should be a big red note in WPEngine's support garage. You don't simply disable all cookies and not tell anyone.
• WP-Cron is broken by default. Posts miss their schedule all the time. I registered a support ticket with WPEngine - they say that they have some internal defaults set that often break wp-cron, and that they would set mine back to fix it. My posts still occasionally miss their schedule. More importantly, why is wp-cron broken by default? Isn't that something important to tell your customers?
• Weird validation - WPEngine overrides core validation routines to do totally inexplicable things like ban capital letters in usernames. What the hell?! Since WP doesn't ban this by default, you get totally unhelpful validation messages like "Your username must only have alphanumeric characters." Adding a simple filter to sanitize_user fixed this, but why do I have to do that?
• Staging is a mess. I use Wordless, a great plugin that allows you to use HAML, comes with great helpers, and breaks functions.php into a folder of scripts. This completely doesn't work on staging, and WPEngine has no solution. On top of that, staging does not use the same caching as production, which means that even if my theme did work - I wouldn't catch many of the above bugs.
• Import limits are agonizingly low. I wanted to import a bunch of posts of a certain category to another site on my WPMU network. Rather than pull the raw SQL, it would be nice to use the WP importer/exporter so I can pull media data, create taxonomies, and so on. After all, that's what it's built for. But WPEngine has a 256MB memory limit (!!!!!) which means that my imports have a paltry 1.6MB limit. What can I do with this? I ended up having to find a Python script to split my imports into manageable chunks. On other hosting I would simply raise the memory limit. This was a real pain.
• Just as I was writing this post, I lost all of my restore points. Wow.

I'm sure I will find more.

A lot of this would be alleviated by having a simple guide to WPEngine's quirks - like a "What to watch out for in production" article. But no such thing exists. And until the staging environment is a proper staging environment, with the same exact caching, I will continue to find bugs in production & only in production.

Suffice it to say, WPEngine is anything but "Hassle-Free Wordpress Hosting."

Edit: Since this post, I've come across yet another: WPEngine's aggressive site caching actually caches the blogname of my main site onto several of my child sites every morning. That's right, the title of my child sites actually CHANGES every morning and I have to empty the cache daily to set it back. No database writes are done, nothing is wrong in MySQL. This is WPEngine caching my blogname - and getting it wrong. I can't find a GIF to explain how I feel.