Right now I'd recommend anybody to just go with Clojure. Other then that, it's a pretty common-sense article. The Unix choice is controversial but truth is, most powerful lisps are not windows-compatible and definitely not windows friendly. Between emacs and vi I'd suggest the one more familiar, or a third one if that's the case. Lisp has a steep enough learning curve not to need a new environment to learn alongside.
I love Clojure, but SBCL is seriously ass-kickingly good software as well. It's a matter of taste, I suppose.
Go with Clojure if you:
Want / need to interop with Java
Want to use Clojure's cool STM
Want to be specifically functional
Be one of the cool kids.
Go with SBCL / Common Lisp if you:
Want to use cool stuff like Cells & Hunchentoot
Want to make your way through PAIP, PCL, On Lisp
(In other words, lots of documentation for CL!)
Want a multi-paradigm language (CLOS is awesome)
Be one of the cool kids.
I agree with you, but I thought I would add that Clojure has the dataflow library in clojure.contrib that does some of the same things as Cells. It doesn't have Mr. Tilton, though. ;)
You raise a good point: Clojure is being actively developed, while the core of CL is stable. If you care about language velocity / activity in either direction, there is a difference between the two.
