Scratches on tools are like callouses on a mechanics hands, or wrinkles on an old guy, they show use and experience. If you're worried about scratching tools, stop now and don't buy any.
Buying tools isn't that hard. It's not rocket science. There have been way too many threads lately with people wanting their hands held as they face such difficult decisions which ratchets, hex bits, wrenches, or fill in the blank tool to buy.

Sometimes life requires trial and error, you need to get a tool, actually use it, and learn from your own experience.
As for the question at hand, full polish offers easier clean up but, may become slippery when covered in coolant or ATF. Satin finish may offer a better grip when covered in fluids but, tend to require a little more effort to clean up.
It's strictly a personal decision as it's your hands that will be actually using them or in this case polishing/dusting them.
