I nabbed this app on an impulse buy after seeing it on a particular website. It is sadly, not more than a novelty at this time. A short video plays on first launch, leaving you with only the faintest idea how it works. The user interface was unintuitive but detailed. This app could use a LOT more work into ambient filtering, as it was largely useless due to interference from just about anything. Hopefully, a more concise tutorial and intuitive interface can be worked in. Using an iPhone 3G S

Down to the decimal accuracy. Just point it at a wall and get the distance. Once it is calibrated right it is very accurate!

I read a bunch of reviews, both good and bad and was fully aware of the fact that this app really falls into the experimental category. But the idea is exceedingly cool and this particular app seemed to be the one to get. As per the author's instructions, I viewed the instructional video and read all of the documentation twice. Nonetheless, I was unable to get the app to work at all. It never gave me an accurate measurement even once. In fact, it never really gave me any measurements at all that were not just noise. Undeterred, I read the docs again and attempted to do a manual configuration of the app. Unfortunately, if you're lucky enough to find the information on the "custom" calibration for the app, the docs are obtuse and don't really explain what the settings in question really do.As a last resort, I contacted the author through the contact link on their website (which contains almost no information about the app itself). It's been two weeks now with no response whatsoever.I'm sure this sort of technology for the iPhone will improve over time, but at the moment neither the app or the company are ready for prime time.

To all those people who have first gen iPhones leaving 1-star reviews: THIS APP ISN'T MADE FOR YOUR PHONE!! The first gen iPhone's microphone isn't nearly as good as those in the 3G and 3GS. It is not as sensitive to various frequencies. I moved into a new apartment a few days ago and this app has worked great. It measures rooms to within a couple inches, which is good enough for positioning furniture. I checked the values with a real tape measure. My wife is amazed. Just make sure you watch the intro video to calibrate your device before using and you're good to go.What these developers were able to achieve on the iPhone really demonstrates the capability of this platform while also capturing the spirit of innovation that, in my opinion, is what make Apple products great. Their drive and determination to do the seemingly impossible is amazing to me. My freaking cell phone is now a tape measure. For real. Like a bat or dolphin. It's insane. I love science.