Vlado mentioned at SIGGRAPH, that they basically gave up and has gone from OpenCL => CUDA => "let OptiX handle it" => "OptiX7 w/ RTX". Do you have a CUDA and/or RTX comparison?

P.S. It's awesome you're still working on Indigo!

OpenCL seemed to have comparable performance to CUDA when we stopped using CUDA. I don't have comparisons with RTX on hand. The main problem with OpenCL now is not performance but vendor/driver support. For example the Apple OpenCL drivers are pretty buggy.