Hi.
I recently had one of my dogs chipped and the cats and the other dog are having it done this month. My vet said that they have improved the chip. It has little "legs" on the side now that hold it in place. That is probably not the right word to use, but he said it will stay put because of the rough edges. I would definitely choose microchipping over tatooing, but I know some people actually do both!
The chipping procedure did not appear to be uncomfortable for my Honey at all.'
Good luck. You will feel more secure when it is done. I promise!
Logan