Has anyone done any design work using LT Spice

I found this spice program completely free from LT Technologies and was wondering if anyone has played with it for crossover,power supply, or amplifier design?
Also it seems to be well supported with a yahoo group.
Yes, LTSpice is an excellent tool, and is my SPICE simulator of choice. The recent revisions are especially nice, with good multiprocessor support - which means faster analysis or higher iteration limits for certain analysis techniques.

Its main drawbacks are that its very much a tool for professionals and those who are familiar with SPICE techniques and limitations -- it's NOT documented for a beginner. It's also of course not an integrated software suite with PCB design, extensive schematic drafting, autorouting, etc. etc. - but in my book that's a good thing, because I feel that autorouters are responsible for a great deal of poor layout, hence poor performance, in modern audio gear.

The Yahoo group is also an excellent source of support for LTSpice.