I use E drawings for viewing dxf dwg files when I cant be bothered to fire up solidworks.
What really sucks is that Solidworks keep phasing things out making you upgrade all the time and dropping backwards compatibility

I don't have to pay but its still a pita to use when customers send you old files or files from the new versions you have not upgraded to yet, saving as step or iges just to open files leads to all sorts of busted up models
Catia V5 can be found free on the web if you look around, its pretty good especially if you have not used other software and got into certain ways of doing things.