does anyone out there own one of these (or another one)?

I own the SoyaJoy soy milk maker from http://www.soymilkmaker.com.

do you like it?

Yes! I love it. I use it to make tofu and soy milk at LEAST once a week.
Sometimes twice or more.

are there ones I should steer away from?

The cheap ones from Ebay. Plastic filters are bad.

how well do they work?

Great. I can produce soymilk for less than 20-30 cents for 40 ounces and I
can control what goes into it. I'm not vegan or vegetarian, rather just try
to eat healthy, but I'm still very conscious of the amount of crap is in
store bought stuff.

can i really make tofu in a half hour??

It takes me about an hour. Two batches of soy milk(~30 minutes),
curdling(~5 minutes), and pressing(~25). And damn it's good! Yield about a
pound(using techniques described in the Book of Tofu.)

I highly recommend the unit I have OR you can go for the soyllife machine
which is the same machine but it is UL listed and has a power off switch.
And if you order online you get a free tofu kit. However, I have not used
this machine and can only go by what other people have told me.

Christopher