I love my
True Talker. I've had really good luck with it, but what's more important than the product is timing. What the deer want, is what they want...there isn't one fool proof call/style. Many times, you'll still get ignored even though you think it's perfect timing. I look at it like a batting average, and if I can bat over .300 I feel like I'm doing something right.
The shorter grunts seem to be the ticket. I use these more often. If they don't respond, try mixing it up and use a long drawn out grunt, snort wheeze, or if you have the True Talker, try mixing up the pitch of the grunt.