[campers]

The SDK's were slow to update, the Java App Engine doesn't support Java 8 yet the Python and/or PHP version are behind a bit I think. There's a bunch of bugs which haven't been resolved after a long time. The instances were underpowered for the price, Java ones took a long time to start up which compounded issues with the auto-scaler.

I used it a little bit a few years ago and despite the issues with the original platform I'm quite interested in the new Docker based managed-vm app engine platform, where you can build your own images and have much better control, and compute engine pricing.