We've learned of a new source for comparisons of 3D printers: FindTheBest.com, which is a comparison and review site for products and services of all types. Now they seem to have added a section for 3D printers, at least the less expensive ones.
Their 3D printer section lists over 30 different devices as of this writing, and presents basic specification information about each device. You're able to sort the list by key factors such as price, number of extruders or layer height.
While the site does provide basic pointers to different machines and can provide an introduction to the most common personal 3D printing options, there is a lot more to the story.
The list shown is a mix of machines with different technologies, materials and service options, all of which should be considered when choosing your 3D printer. Certain technologies are better for printing particular geometries and certain materials are better for particular applications. Depending on your circumstances, you may want a device that has a well-developed support service, or perhaps a large sharing community.
The devil is always in the details, but with this service you can at least get a reasonable list of options to investigate.