Guess I'm the first to vote and vote both......but the thing is, if I was only gonna do one, I'd definately grunt. There are a lot more times whena grunt will bring a deer your way than when rattling will. I pretty much only rattle during the peak of the pre rut stage when it seems to be a little more effective. I almost never rattle once I can actually see a deer, but will many times grunt at them when in sight.

It's also important to know where you are in terms of deer, for rattling.If you have a buck/ doe ratio closer to 1-1 it will be much more effective.....if it's more like 20 -1 it won't produce much
Just my thoughts...

GH