"Reasoning" is being a little generous: I happened to develop a setup which is a duct-taped mishmash of VPSes and external services, and every few months I pay for it with a phone call at 3 AM in the morning (local time) that says something has broken.

These days I'm attempting to move things off of my VPSes where there are good, stable options which don't require huge engineering efforts to use. SendGrid for email was an early, obvious choice. I'll be migrating many of my blogs to WPEngine fairly soon. (I'll write up my rationale for that at length after it happens. They're a client, so take my arguments with a grain of salt, but it became painfully obvious when working with them that it was the right call.)

If I got a do-over on my two main software products I would probably re-write them to use Heroku over self-hosting them on my VPS. It would have avoided ~6 minor service disruptions and ~2 catastrophes in the last year, plus saved me about two weeks of lost billable time. (Mostly lost due to having a very involved migration from Slicehost to Rackspace which went fairly poorly, principally due to failing to invest another few weeks preparing thoroughly for it.)

I can't justify a rewrite of BCC or AR at the moment to migrate to Heroku, though, as they're both multiple weeks of work with high probability of breaking something, and my anticipated costs due to I'm Not Always A Sysadmin But When I Am I Only Fail On The Hard Stuff this year don't quite justify it. (Please, please, nobody buy Rackspace to shut it down. One migration was enough.)