Ask HN: What's your favorite PaaS?

Hi all! I have been out of the Ops world for a bit and I'm dipping my toes back in. I'm trying to get a lay of the land around what's happened in the PaaS space since I've been away.

Right now it seems like Heroku is still going strong. I also see that there is Pivotal Web Services, which I guess is hosted Cloud Foundry.

I can't seem to find anything else with clear and obvious marketing that says "hey, we're a PaaS". Are there other platforms out there I should become aware of?