Dismissed Wordpress for many years, then I found WPEngine (I know, mentioned below, but I have some points to make). Edit: Not affiliated with them in any way. Just a really big fan.
My number one reason for WPEngine is their excellent support, both in terms of response times and general knowledge. They have never let me or a client down.
My time is money (or the client's money). Yes it's much more expensive than self-hosting, but my hourly rates are much more than their professional plan costs each month. One unfortunate issue and they'll spend more on paying me than they'll save on hosting elsewhere for a year. This is also how I "sell" WPEngine to new leads. It's not a hard sell.
I now have 12+ client sites there. Some several years and none have suffered a single issue of a compromised site. I've actually used WPE's (free) service to migrate compromised sites to their platform and get them cleaned as a feature to garner new clients.
The WPE interface allows me to switch between them in an instant. Add to that general performance/caching, security/firewall, automatic updates, daily snapshots and reverting to a previous version with one click, on-demand backups, the staging site functionality, free automated SSL certs, CDN (pro plans), etc etc
It has come to the point that I don't accept any projects that don't agree on hosting there.
PS Fought battles with many different CMSs --e.g. don't even get me started on Joomla or even Drupal-- and don't believe that wordpress is any more vulnerable than other CMS sites. Moreover, there are so many WordPress developers out there, that I can safely promise that me getting hit by a truck is really not a problem.
Edit 2: I limit plugins to the absolute minimum. I avoid free plugins whenever possible. Buying highly rated plugins with support from places like ThemeForest is really really useful and well worth the money.