KiCad is very good, and works well, but has a few glitches and 'quirks' that some folks don't like. It is, however, free and open-source.
I tried out Altium designer, and it works really nicely. It also has a /much/ larger component library. You'll also get a lot more of the more professional features, and it feels like a more professional software package.
But regardless of what package you use, you will inevitably find yourself making component diagrams and footprints. In my opinion, it's easier and quicker to do this in KiCad than in Altium. In terms of overall usability... eh. There's pros and cons to both.
I haven't used Eagle or DIPTrace, so I can't really comment on them.