[Ambrevar]

I've never used them myself, so in all honesty I have nothing to say about them! :p

That said, I support free software and I believe a proprietary compiler is not a good idea :(

[TurboHaskal]

Ideology aside, most proprietary compilers (mostly for Forth, Pascal and Lisp) I have used are of _excellent_ quality.

A lot also provide you the source code once you pay. AllegroCL is one of them I think.

[pjmlp]

The FOSS experience is a poor imitation of Lisp Machines.