In my opinion, these are the best picks around. You have very good control over your picking technique - it's like if the instrument was "closer" to you than with other picks. Using them is a quite direct way of playing the guitar. They are especially good for lead guitar and funky rhythm with strong strokes but I use them for any playing style or genre. The resulting sound is quite brilliant; for parts that need a more soft and dull sound I just use my fingers.
The picks last quite a while. I buy a new pack of 12 maximum every six months. That also means that they're relatively cheap. But keep in mind that they don't stay as sharp over time. The picks get a little rounder but can be resharpened through cutting it.
The only real thing Dunlop could have done better is the grip. When being new, they have a slight grip (not comparable to these Ibanez sand paper picks I used before). But this slight grip wears off relatively fast so the picks tend to slip through sweaty fingers. My solution is carving chaotic patterns in both sides of the picks with a sharp tool. This enhances grip quite reliably.