One of the most useful features of any viewer is the ability to compare similar design revisions to determine any differences. Starting with DFM Now! Version 8.1.5 and higher, Compare Layers is now available free. Previously it was only available in FAB 3000 (our full featured CAM editor).
Here's a quick tutorial movie showing how to compare two similar layers and easily find the differences using the free viewer DFM Now.
DFM Now! - The Best Free Gerber Viewer
FAB 3000 (CAM Software)
FAB 3000 is a professional CAM software package targeted for anyone who would like to have "high-end" CAM software to run advanced DRC/DFM verification, generate component centroids, create SMT Stencil pads, Panelize PCBs, and perform many other useful features. Download Now
Get Numerical Cloud for only $75/month. Includes FAB 3000 (CAM Software), ACE 3000, and EasyGerb. Runs on up to 3 computers. Easily perform all Design Integrity Checks on your Gerber and ODB++ files. No contracts and cancel anytime.