I suppose it’s worth learning anyway, it seems to give a very precise control over compilation, has a bunch of libraries and is very well documented. Also, an email to support@franz.com, which turned out to be a very silly question, was answered promptly. One day, I’m sure I will buy the Professional version!

However, I can’t always use this as an experimental Common Lisp platform. Today I wanted to try out Genworks, but when I tried to load it, I saw

Error:
An explicit gc call caused tenuring and a need for 786432 more bytes of heap.
This request cannot be satisfied because you have hit the Allegro CL Free Express heap limit.
The Student Edition has an unlimited heap.
For more information on the Student Edition, see http://www.franz.com/downloads/student.lhtml.
For an evaluation of our Enterprise or Professional Editions please contact us at sales@franz.com or (510) 452-2000.
    [condition type: STORAGE-CONDITION]

I don’t want to pretend to be a student, so … back to SBCL!