Yes, I run both WE and JFW happily on the same computer. I can even run
them at the same time, though hearing two voices with a slight delay can be
somewhat interesting and they do interfere with each other if run
simultaneously. I have not encountered any difficulties running
both. Just make sure you have hot keys set for both engines so you can
stop and start whichever you like, and don't have them both set to begin at
startup, or you will have a bit of a mess.