I use a selection of CAD packages, and I would prefer to use Proteus over say,the new Altium Circuit Studio offering as I have said in a previous post, however, it is not just about "value for money" with a design tool, if you are starting out and never used one before then fair enough, go for Diptrace or <insert another CAD package here> it is about what you are comfortable using and what you / your company are using.
I have used EAGLE for quite a number of years now, and yes, there are better value packages around etc, but I also use Proteus and Altium Designer, even KiCAD at home, and I have gotten used to all of their quirks and oddities, they all have them, and I am happy using any of those 4 to do design work.
I have used DipTrace, and although, a decent package, a few quirks some say they add better usability, but again, it depends what yo are used to, I had no requirement to learn another entry level package.
The only package I would like to learn more about is OrCAD, I have used Design Spark for a brief period of time, and didn't really get on with it, and the more powerful Pulsonix, which again, I didn't get on with.
I have used CADSTAR (which I detest) and Ranger XL in previous lives, they can all produce valid PCB artwork, and if you have a part library built for one, that is proven to be correct, you would have to start all over again going to a new package.
If you don't like a package, use a different one, you will find one that works for you eventually.