Some great advice on this thread. I'd suggest getting yourself a tape or cd and see which type of call you can make sound the most realistic. Record yourself and play it back to see how you sound compared to the real thing.
I've killed turkeys that took a ton of sweet talking to get them in range, but I've also had some almost run down the gun barrel when they heard a few purrs and a cluck or two.
Whichever type you decide to go with, practice, practice, practice. Running a turkey call is about like playing a musical instrument, you just can't make it sound too good. It won't be necessary to become the first chair in an orchestra, but the better you sound, the more turkeys will buy what you're selling.
I enjoy going to a state park with a good population of turkeys and practicing my calling on them, especially when it gets closer to the season and the birds become more cooperative.
Luck Counts, good or bad