Back before I got Ruby, I saw on Rugosa's website that they recommended Merial recombinant for the rabies vaccine as they said they had fewer problems. When I first got Ruby, my state required that she get a 1 year rabies vaccine. I remembered to ask for the Merial recombinant rabies vaccine…she got it and never got a bump. Last fall when I went to get her 3 year vaccine, I forgot to ask for the Merial recombinant and Ruby got a bump at the vaccine site (I checked and it wasn't the Merial that was given...can't remember what they said she got, though).
So I don't know if there really is a correlation to that particular brand & type of rabies vaccine, but because Ruby didn't get that the second time around and got a bump, from now on when I get rabies done, my 3 dogs are getting Merial recombinant.
Also, one other thing (for people showing their dogs) that my kids breeder mentioned and other show people mentioned is that if doing the rabies vaccine, always get it done on the non-show side...just in case there is a reaction.