Any good? Who's used it?

I've tried RS in several languages...I suck at learning languages, it didn't help.

I am using the total immersion package right now.  I took spanish in HS and am taking it now.  I am about 3 hours into the course and my spanish is coming back.  I can let you know in about a month.

They are great, and really work.

I've tried Rosetta Stone, but you have to dedicate time to be in front of your PC.  If you are really into visual cues for learning this is probably best for you.
I'm starting the Pimsleur Spanish series.  It comes on CD, which I ripped to my iPod, for listening in the car.

I believe you can get introductory / sample sets for both, either for free or very cheaply.  Try them both, then decide what you want to invest your money in.  Also, once you choose what you want, look for used language sets on eBay, craigslist, etc. to save some $$$.