I've got the 125 amp version of this Lincoln unit and use it exclusuively with flux core. (My machine runs on 230v and looks exactly like the 135 model.) I had it set up to run MIG but found that it was somewhat 'toy' like compared to larger MIG machines so I went back to flux core. For me the machine really shines as an 'always ready to go' flux core machine. (I don't mind the slag. If you get the current and feed set correctly and the metal is clean the slag is hardly an issue as it comes off easily. You do have more fumes to deal with using flux core.) I regularly weld 3/16" structural tubing without maxing out the amperage. Having a steady hand is probably a matter of practice and technique. I like to think of the weld puddle as a crucible of molten metal that I keep filled and move ahead as it starts to overflow. If it isn't about to overflow I don't move it ahead. At these low amperages you can go bare handed or wear a light leather glove on the torch hand and use a long gauntlet weldors glove on the other hand. You can use the heavily gloved hand to guide torch tip without a risk of getting burned. Use a helmet that has an automatic darkening lense and use a magnifying insert. It's important to be able to see what you're doing. As you get experienced you'll realize that you can also tell a lot about the weld by the sound that is being generated by the arc. Don't forget that the arc produces strong UV. Protect your skin. The other thing to remember is that welding is similar to painting in that preparation is key. Clean metal is a must so get a small 4" grinder and an assortment of abrasives.
Chris