Save your money! I would not bother with either. I have not found the Furminator of much use...neither for my own dogs or for the boarding dogs with different types of coats. My Furminator is sitting in a basket collecting dust.
I use a undercoat rake...and find it is the best thing for getting the undercoat out for all breeds....from my Rotties to the Goldens, Labs.,and everything in between.
I'm probably in the minority here....but I don't like it.
Gina