Do you find Lispworks superior to SBCL / Emacs?
Any tips for other programmers on what to do / what not to do when it comes to production level lisp programs?
I use both.
As for tips, there are probably a lot, but I have to take a break from HN right now to attend a work meeting. :-)
SBCL is better in the sense that almost everyone who writes an open-source library for Quicklisp distribution is going to test it with SBCL, so most of the time Quicklisp libraries just work with SBCL.
Testing with other Lisps, including Lispworks, is not quite so automatic, so there's a little greater likelihood that something might fail to work.
That being said, most libraries I've tried with Lispworks have worked without any trouble.