Nice. I had one from a set that came with a cheap 1/2" router: supposedly a V groover, but the carbide insert was about 1mm off centre. I forgot once and got as far as tightening the collet, but mercifully never started the motor. It _probably_ would have just shaken itself around a bit, but possibly not.
Now I just bin suspiciously blunt or odd bits when I find them again. It isn't worth taking the risk, IMHO.
By the way, I can't remember if you said your router is 1/2": if so, kitchen fitters' straight 1/2" cutters (for worktop jigs, etc.) are often good value. They're usually quite reasonably priced, and those from the better makes are often priced a lot lower than sizes either side. I've got Freud, Wealden and Axminster ones and all have been excellent. The Wealden one I have is very long, and got used as an improvised planer years ago, before I got a proper machine. It is still wickedly sharp though.
They're great for rebating, slotting/morticing -- all sorts really, and the other thing is that almost all straight cutters go blunt first on the ends. As worktop bits are long, there's usually a lot of sharp edge left, if you can contrive to make good use of it somehow. There is a good argument I guess for doing the first bit of a plunge cut with a brand new cutter, and switching to a more worn one for deep in the rebate or the mortice, where it can't be seen.
But then I come from the school of Never Throw Anything Away...
