I actually really like DipTrace for basic schematic/PCB design work. It's very simple to use, and so far I'm using it for all of my products. It's really lacking in many of the features/interactions that you expect from software in a production environment, though. For example, it's very easy to make new patters/components, but then managing them, propagating changes, is complete crap. The library management is crap. Their "grid", especially as it pertains to switching between metric and imperial, is complete and utter crap. There's a lot of crap that pisses me off about it.
But all that said, I use it and really like it because the core process of creating a schematic, laying out boards, making my gerbers, etc is a joy to use. If I were doing anything moderately complex, or working in a larger environment, I probably wouldn't consider it, I'm afraid. I'll bet it would work very well for a large percentage of the work that most of us do.