Show me any CL library that is competitive with numpy+scipy. Similarly, I do a lot of distributed memory work, for which MPI is necessary. For CL bindings, all I know of is CL-MPI and mpi4py trumps it in every way. I need parallel linear and nonlinear solvers, petsc4py fills that role well, but there is nothing similar for CL. It's also crucial that it work reliably in unconventional environments such as BlueGene, this is rare for proprietary implementations. I don't really like Python, but these libraries and it's portability make it a functional environment. I don't think any proprietary implementation is prepared to step in.