With C25 shielding gas and solid wire the 180 has a nice clean running arc that has a good level of crispness to it. This would be my recommended set for solid wire. I find CO2 very annoying to deal with very window of operation were it produces ok results.
The feeder tops out at 500 ipm if you mainly going to be welding 1/8" - 1/4 ", with solid wire, I probably set this unit with an .035 solid to guarantee I could get the top end amps out of the unit. For 1/4" critical applications i go with the stick welder over the 180. With solid wire Lincoln 180 units and best on 3/16 and thinner. The top ends a little lean for 1/4" when you life depends on the weld. Self shielded fluxcore will burn in better on the 1/4". For handling load stresses a 7018 is gonna give you a superior weld to the self shielded fluxcore