But is it really worth the headache of such a Frankenstein architecture?

I initially fell in love with the "no sysadmin" aspect of App Engine, and started building apps around it. Eventually I realized that (for me, anyway) the upside isn't really worth the trouble of having to contort my apps to work in Google's sandbox- can't run SQL, have to deal with datastore timeouts, CPU timeouts, etc. When you're done coding work-arounds for all of these things, are you really coming out ahead?