In the course of looking for the proper top bearing router bits to use with my Glenn, Rennie, Robert, Shop Notes, et al. inspired variable finger joint jig build, I stumbled on a discussion where someone recommended insert bits. Hadn't heard of them before. They are pricey, and primarily used commercially, but when dull you need only rotate the insert for a fresh cutting surface, or install a new cutter--kind of like the carbide lathe tools. So, an initial high outlay for the bit and pack of ten inserts keeps me routing for a very long time...the equivalent of twenty new bits. Is anyone here using this kind of bit and if so, are you happy with it? Any drawbacks? Are they safe?