As my tests showed, these router bits are a complete waste of money. The industrial and scientific marketing is misleading, as these bits barely lasted through one small project. The only pro is that they were affordable, but that's not worth the headache of constantly replacing them. Do yourself a favor and invest in higher quality cutting tools, these were a huge disappointment.
Pros
Produces clean and accurate cuts on wood, composites, and laminate materials.
Cons
Works only on materials that are less than 1 inch thick.
This was my first use of little pilot bits. Worked really well for adding curves to my bandsaw scroll projects. There were many tight corners where the normal stock pieces got in the way of a good detour. That beat was just a gimmick. Note that the brass pilot is attached to the racquet and does not rotate. There were no burn marks on the cherry. Highly recommended.
I needed a 1/8" wheel in shallow water. This bit with ball bearings was much more compact and tailored to the needs. A smaller diameter is also fine if you want to round off small radius corners. The overall diameter is smaller than a typical 1/8" bit and the feed rate is therefore slower. Not a replacement for a ball bearing pilot, but a nice addition.