Personally, I like the vertical pin because I can align it with the back-side of the leg (on a deer), and it mentally helps me. I personally like a single vertical pin w/ an adjustment mechanism for different distances. This has greatly helped my accuracy, and it just works for me.

Check out Vital Bow Gear sights. I've been using them for several years now and they are very nice. Crazy bright, tough, simple, and they have a bunch of different sights to choose from. Check em out!