I've done six installs and have had a generally favorable experience with
all of them. This beta has caught stuff that others haven't and has deleted
spyware that has resisted repeated software and manual removal. (If someone
launches those miserable TV Media folks into low Sun orbit, that's fine with
me).
However, it's not enough.
Unless the industry (basically, Microsoft) both hardens its software and
takes world wide legal action against some of the bigger and nastier spyware
purveyors, the future of the personal computer / system software paradigm is
pretty much a dead end. There's no future in a product that requires every
user to have advanced system administration skills to operate, and there are
millions of computers out there that are causing their owners grief or
financial loss right now. We've all heard the stories or worse, told them.
M$ Antispyware beta is a good first effort, but just the first step on a
long road.