Has anyone made use of ASE (Android scripting enviroment) for anything other than proof of concept apps?
What are the major limitations?
Any feedback would be great.
As this stage, using the ASE as your actual product's platform would in general be a bad move if performance is critical. It's great for rapidly prototyping something and/or verifying your understanding of how the API works. But the performance hit is nontrivial. This is the approach Google recommends, too:
With respect to the interpreters ASE provides, Lua and Python are both cross compiled C binaries that run in their own process. CPython is significantly more performant than Jython (especially since Android does not currently support JIT).
As for the Android facades, the API is primarily focused on making it easier to write scripts than on the performance of those scripts. That said, remember the adage "measure first, then optimize." ASE is about rapid development after all.
If you have performance concerns for your application, it's probably better to use the standard Android SDK (or NDK) where you'll have more control over the system.