At the end of August, I wrote a review about the Flir One infrared camera for the iPhone 5. This may have been the first infrared camera designed to be used as a toy; the quick start guide that comes with the camera even says it'll help you gain a super power. At the time, it was selling for $350. The price has since dropped to $250. Unfortunately, us Android phone users were left in the dark visible light spectrum, until now. Seek Thermal has come up with a $199 infrared camera that works with several models of iPhones and Android phones (full list here). I tested this camera with my Samsung Galaxy S4.
The Basics
The Seek Thermal camera is very small, and plugs into the USB port at the bottom of the phone. There are no batteries to charge, no special cables to use, nothing like that. All that's needed to get started is to install the Seek Thermal app from the Google Play store.

Size and Shape
It's tiny. Because it connects to the phone through the USB port, drop it once and it'll surely be toast.

Software Options
The software is similar to the software for the Flir One. It takes photos, records videos, there are a bunch of different color palates to choose from, it has a spot meter function that is supposed to display the surface temperature of whatever you're pointing the camera at, and a few other options.
Resolution
I've gotta be missing something here. The Seek Thermal web site says "206 x 156 Array", and "32,136 Thermal Pixels". My $2,500 Flir E6 camera has a resolution of 160x120, giving a total of 19,200 pixels. Given those numbers you'd think the Seek Thermal camera would produce a much better image, but that's definitely not the case. This makes me question the validity of judging an IR camera by its resolution. Thermal sensitivity might be a nice metric to use, but I can't figure out what the sensitivity of the Seek Thermal camera is.
While the $250 Flir One camera has a second optical lens which blends optical images with infrared images to give an easy-to-understand hybrid image that outlines the high-contrast images, the Seek Thermal camera doesn't have that option. The two images below were taken with a Flir One camera, with and without MSX turned on. These images were taken during the summer, when there wasn't much of a temperature contrast.

The real 'infrared information' you're getting from the two images above is identical, but the image on the left is much more pleasing to look at. That's the beauty of MSX technology, and that's what you're missing with the Seek Thermal camera.
Image Comparisons
Here are a few side-by-side image comparisons of the 206x156 Seek Thermal on the left and the 160x120 Flir E6 on the right. First, a shot of my basement. These were taken just recently, giving some nice thermal contrasts.