Not to go against the grain, but my son picked up one of the inexpensive NWTF slates made by Woodhaven while at the NWTF convention in Nashville. For a $20.00 call I think it sounds great and it's easy to use. In a month he has learned to yelp, putt, purr, tree call, and cut on it. I intend to use it some this weekend.
The best pot call I found at the convention was the Robert's Brothers glass over slate, made byJerry and TommyRoberts in Georgia. This call was used to win the friction championship this year. I got one with a purple heart striker and I really like the combination of high, low, sweet, and raspy sounds I can get out of it using different strikers and surfaces. My dad bought one after seeing mine and has killed (or called in for others to take) 4 turkeys so far this season. He likes the aluminum striker on the glass, which makes a raspy but higher pitched yelp. I used a MAD plastic striker on the glass to call in three Sunday.
Here is the link:
http://www.robertsbrothersturkeycalls.com/m100.ivnu