I do a lot of welding on road construction equipment at work, and for me arc is more relaxing, I can just zone out while I'm welding.
Even though I like arc more, for speed I use the pulsed mig setting on our Lincoln Power-mig 350mp's with 90%Argon, 10% CO2 and .045 solid core ER70s-3. It's fast, penetrates awesome, no splatter and there is no clean-up when you are done. And there is no messing with voltage/amperage on the pulse setting, just wire speed, and the welder chooses the best v/a for the wire speed and wire size being used. You can just crank it up and if its too hot you just move faster.
I also do quite a bit of hard-facing at work too with arc and wire-feed. If I had to choose any type of welding to do for a living, it would be hard-facing, it's just fun to do. You have to look at previous wear patterns, and figure out what types of welding patterns will prevent wear on the parent metal.
