Disclaimer: I don't own a Taurus 709 slim. Although I did pick one up at the LGS/indoor range where I have a membership and dry fire it, and it fits my hand.
The folks at the Taurus Armed forum did a poll on the 709 "How has your 709 worked" recently (last post June 2011)
243 folks voted
93 said "no problems" 38.27%
52 said "fte" 21.40%
18 said "ftf" 7.41%
11 said "loose magazine" 4.53%
21 said "light strike" 8.64%
48 said "off on sites" 19.75%
Now, unless lots of folks are not telling the truth in this poll, it looks to me like over half the people have a problem with their 709.