I have an old Kayline (same as the STC snap top) on my 69 and it is great. I also have a brand new Fastrac waiting to go on my'72. I went with the fastrac for my '72 based on recommendations and testimonials on this site and CK5.com. I haven't been impressed with any photos of the bestop. They never seem to fit quite right. STC (
http://www.specialtytopco.com/) makes good products from what I have seen. I got swatch samples prior to ordering the fastrac (actually ordered mine through
http://offcamber4x4.com/ because they were extremely helpful in my decision making process and, at the time I was a CK5 member and got a discount.) I went with the white because it was almost a dead match to the off-white interior in my '72. As soon as the weather gets nice enough and space is cleared in the garage, my hard top is coming off (for the first time) and I'm going to install the soft top.
You can download installation instructions for the STC products from their web site. It shows you exactly how many holes
you will need to drill into the body of your truck.