Lisp Machines weren't that successful. I was their target user, and I ditched Symbolics to use Lucid on Suns at the first opportunity.<p>The Lisp Machine software was appallingly baroque. Everything had every possible feature. There was no design, just implementation, and lots of it. The manuals took up a whole shelf, and it was generally faster to write something yourself than to find the predefined function that did it.<p>A lot of (arguably most of) the badness of Common Lisp is Lisp Machine culture showing through.