Learn on 6011. Once you can make a nice smooth bead with them you are doing pretty good. They are fairly easy to start an arc and make a bead with, pretty tough to make a 'nice' looking bead with. Once you master that move on to 7018. For 7018's your metal has to be clean, you have to have good, fresh (dry) rods, and you have to use the proper technique to prevent slag inclusions or porosity.They are probably one of the toughest rods to use properly, but once you figure them out they will be your favorite for most all fabrication projects (they are also amongst the strongest.) The only time I use 6013 is for light welding that requires shallow penetration, I never have found a need for 7014.