Do you use MagicJack?

We've all seen the commercials: "Introducing MagicJack, the breakthrough device that makes your monthly phone bills disappear!"

And if you're like me, you chuckled to yourself and thought, "Too good to be true - and even if it was, it's no deal."

When it comes to emerging technology, usually the late-night infomercial route isn't the way to go. But according to the Wall Street Journal's Walt Mossberg, the $40 thing actually works.

First, the wager: Maker YMAX says all you need to do is plug your phone line into the butane lighter-sized device, plug its USB connector into a PC, and voila -- instant Internet phone calls.

Savvy ZDNet readers know that Vonage and Skype have been doing this for years, but it's all about price: for $20 per year, you get calls to and from any phone on any telephone network, landline or mobile, in the U.S., Canada, Puerto Rico or the U.S. Virgin Islands.

Meanwhile, Vonage costs about $20 per month for 500 minutes.

Anything else requires a small fee, but you can move the device around with you -- such as overseas, to make free phone calls home.

Here's Walt:

The call quality was good, except for a few times when the connection got scratchy for a second or two. Most of the people I called said they couldn’t tell I wasn’t on a regular call. The system offers voice mail, call forwarding and conference calls, and you can save contacts.

Turns out it's not all bunk, even if the company's in hot water over its cellular femtocell service.

Still, some folks say they love it -- and some say it's a scam.

Have you tried the MagicJack? What did you think? Leave your experiences in the comments below.