[nyir]

Yes, there are definitely huge speed gains possible and if you choose an implementation which is still interactive you get the benefits of both (I know one particular example in CL: teepeedee2, there are some blogs posts, e.g. http://john.freml.in/teepeedee2-c10k or so).

[616c]

I have seen it come up many times, but is anyone still using it or tried it long term? I checked a year ago or so and it appears both Git commit-wise and blogwise Fremlin had moved on to better things, but when people dismiss Lisp, I don't say it out loud but I immediately think of this project.