It's nice to have atomic guarantees of GILed implementation. For me current CPython semantic is a golden middle: you have pretty fast interpreter without race conditions (for huge part of user code). Due to GIL.
I always like to ask for what kind of task one needs GILless python?
CPU bound? If you are using native python code for CPU bound tasks you are already in a bad place. C extensions can release GIL. For example numpy.
What else?