Love Dunlop picks.  They feel great and never slip out of my hand, and I sweat a lot.  Switched from the .50mm to these because I play both lead and rhythm and the .50 is too thin for lead, especially since I got a new guitar that takes medium strings instead of light. (I mainly play acoustic).  I don't like heavy picks for strumming because I strum very hard and need the pick to flex.  These are the perfect compromise.  I have to note that I'm not a very fast soloist, so very fast players might not find this heavy enough.