I just want to call out something with onnx. It will be slated to improve this year but be very careful what you try to do with it. A lot of basic things don't work yet.

See: http://pytorch.org/docs/0.4.0/onnx.html

The other frameworks are using (in my opinion) slightly misleading language as to how "ready" it is. onnx to Caffe2 is facebook's use case so I could see that being supported fine. It's hard to go much beyond that though.

Support for onnx will be bottlenecked by what pytorch can export right now. The file format just hit 1.0, but it will take some time for the ecosystem around it (including the export) to mature.

Disclaimer: I am a framework vendor who has spent the last few months messing with it for end users writing model import

for tensorflow's file format as well.