[markc]

I prefer loop/recur to TCO. You know exactly when you are, and are not, in tail position (which can be a bit obscure) and the compiler won't let you recur from non-tail.

[lispm]

loop/recur handles only a tiny part of TCO.

TCO means all calls in tail position are optimised, not just the self-recursive ones.

Personally I find loop/recur ugly. It's a partial hack around the lack of TCO.

Though I prefer looping statements like Common Lisp's ITERATE, whose design I like a lot...

https://common-lisp.net/project/iterate/doc/index.html