I have the Accuquilt Go and like it. You can find good deals for it on Amazon, eBay, sometimes JoAnn's sales, etc. It folds up and is portable. There are lots of videos on
http://www.youtube.com that show the Go in action. I like it best for cutting triangles (it lops off all the ears, and pieces match up precisely when sewing) and odd shapes such as the tumbler. I'm not sure it's any better for cutting strips than the June Tailor shape cut mat, but a lot of people like it for strips too.
If I had the space for a permanent setup (and $$$ for the machine and dies), I would love to have the Accuquilt Studio. This is a heavy-duty machine that makes cutting layers easier.
Some people like the Sizzix Westminster Pro, which can take dies from multiple manufacturers (using trays and shims).