You can't go wrong with any of these. My preference is the Boxer over the Tracer. Same wing with more side area for better rolls. I flew a Boxer 1.20 for two years and it was not hard to build and flew great.
The Tiger .60 is also a great plane but like the Kaos lacks side area. My choice here is the Tiger because it is very hard to find a .60 size Kaos kit.
If it has to be a kit look at the Bridi Great Escape one of his most modern designs. If you want to scratch then go with the Boxer or look in RCM for the plans for a Loaded Dice.
You will love any one of these planes. Check NSCRA.org for more info.

Anthony