BITC is a powerful CAD environment which allows you to read DWG files and saves you thousands of dollars.
It comes with all the general tools that you expect from a CAD environment including options to change views, draw geometric shapes plus it has some limited advanced features such as a command line, ADS options to upload and manipulate documents and functions to create and upload macros. Even though this a much cheaper CAD environment than you'd normally pay for such a package, it has a high degree of compatibility with the major programs such as Autocad, AutoLISP, ADS, and DCL routines. However, the big advantage is that it has been specifically designed for use with Windows which means that it integrates much better than most CAD applications. This means it incorporates several unique functions such as the possibility to open multiple drawings at the same time, and of displaying and editing raster images. However, its limited functionality in terms of advanced design options mean that it's probably best used in conjunction with Autocad or another major program
BITC is a comprehensive CAD environment with everything you need to edit and modify basic DWG files.