I've used Easton's Tracer nock and Burt Coyote Luminock and didn't care for them. The former requires the use of a magnet and the latter is finicky how it is installed. Also both are heavy and will greatly alter your point of impact and arrow flight as they change your %FOC.
I am currently using Nocturnals and have take 2 deer with them. I use both the green and the red and they are plenty bright enough. And at only about 8grs heavier than a conventional nock, alteration to your arrow/flight is minimal. I've shot them along side conventional nocks out to 50 yds with no significant change in POI.