Herm Sprenger makes excellent quality prong collars. I have not tried the other brand you mentioned, but if you look at some of the prongs sold at pet stores (Petsmart, for example, carries the "Top Paw" brand) you will see how some of their prongs aren't even rounded at the tips but flat, for example. They're just not nearly as good quality as the Herm Sprenger ones.
Top Paw Training: Kobra's Update - YouTube
Mine does not have a latch. At first, it was a little tough to get on and off, but with practice, it's not that bad. My biggest challenge is just getting Buster to quit wiggling long enough! The Top Paw one I have does not have sharp prongs....in fact, no prong collar should have "sharp" prongs. The tips should be rounded, not pointy. I put the collar around my upper arm and pulled it sharply, to make sure it wouldn't hurt Buster. It was uncomfortable, but didn't even leave red marks on me.
Top Paw Training: Kobra's Update ..
Leerburg Dog Training | How to Fit a Prong Collar