What's the fuss all about? A lot, but please bear in mind the time this was developed. We are now in 2014. We are talking about something about 30 yrs old. A good way to really compare is to go compare with an Apple ][.
There are some enlightening comments from Kent Pitman on comp.lang.lisp, which give a sense of what kinds of features the Lisp machines provided to developers, and why they still haven't been matched by contemporary systems:
https://groups.google.com/d/msg/comp.lang.lisp/XpvUwF2xKbk/o...
https://groups.google.com/d/msg/comp.lang.lisp/XpvUwF2xKbk/X...
To compare it to Apple ][ is a bit too stretched. Lisp machines were developer machines. Machines for professionals in computing technology. We don't have that today. For example, what is the equivalent package or distro that transforms your PC in a "developer machine". You don't have anything like that. All you can do is stitch together some emacs/vi/gdb whatever and search some blogs when you're stuck. And beyond that you are not able to go and fix some IDE bugs _live_.
Today we're missing a machine for professional programmer.
I think multimedia computing, as introduced by Amiga did more for AI, speaking in terms of games, than the Lisp Machines. I do think the jack of all trades approach is useful for sharing data across computers and professions.
It's sad to see the demise of the professional multimedia computer to tablets and tablet-laptops.