Am I right in thinking you need to buy the top ($2500) model if you want to do any CUDA work? Or am I misreading the table and all the MBP models have both the Intel and nvidia GPUs?
For CUDA HPC work, you really need a desktop/server Linux machine that you can use remotely from your laptop. Only the highest end MBP has a discrete nvidia GPU.
Yes to the more reasonable px/performance of a desktop/server Linux backend for HPC. OTOH, if you were doing OpenCL instead of CUDA, the i5 would happily run that as an OpenCL target (albeit more slowly), so that you could do compilation/test dev on any newish laptop.
The intel integrated GPUs also support Opencl, though I'm not sure how useful that is.
I agree that is the better setup, however I'm often on a train or other environment where I can't rely on a connection. In that situation a weak CUDA device is better than nothing.
No, you are right. Only the higher end MBP comes with a separate discrete nvidia card.