I've used a couple of the django-heroku clones, Djangy, Gondor and Ep.io. Djangy is no more. Gondor is nice but lacking critical features (background jobs, caching... etc.), and generally seems like a sideshow to their consulting business. ep.io is ahead in features and quality so far. I have not tried DjangoZoom, as I was a little bit annoyed that they required me to pay for beeing in their beta test program.
Gondor has caching (has for a while) and background jobs will be available this week. Gondor is not a sideshow to the consulting; if anything, it's the other way around :-)