The 3d system rendering system being built in is very useful I always catch a few problems when I look at a board in 3d that don't jump out at me in the 2d views. It works very nearly flawlessly under Linux (using Wine), any bugs there are just a minor inconvenience (such as windows getting lost when you minimise them and you need to switch desktops to find them, something to do with window managers) not a show stopper. The pricing and free level are very good.

I've posted links in our WIKI for various manufacturers that supply 3D models. On the upside, lots of connector manufactures have 3D models but not all. This isn't a DipTrace issue, but instead a manufacturer issue, since too many manufacturers don't supply 3D models. It is a pain in the ass, but worth it in the long run. The major downside of 3D is finding or making 3D models of parts that aren't in the 3D model library, like connectors and non-standard parts. This 5 year old video gives you an feel of how it works on an older version of DipTrace: Many times, the 3D model features has helped me catch part-to-part placement issues before wasting money on making a bad or crappy PCB. A very useful feature for home hobbyist PCB software! With DipTrace 3D mode, you can grab the board and rotate it in any direction to look at the board with your mouse. The best feature I like about DipTrace is the built-in 3D model support, compared to PCB packages that don't have it as a default features.

Diptrace review