If you're feeding it off a 30 amp 240v circuit, Yes it should be sufficient. You'll need to run it hot, which makes the duty cycle quite low on compact MIGs. Forget about using it on 120v mode. You just can't get the power needed to properly fuse anything thicker than about 14 gauge out of a 120v welder. You can get away with open butt joints and outside corners on 1/8", but lap and tee welds will not get proper fusion or penetration, particularly in the flat and horizontal positions.
Small machines can be helped by running a DUAL SHIELDED flux core wire, which is a flux core that still uses shielding gas. Straight co2 works pretty well as a shielding gas in those applications. Flux core will help get greater penetration and fusion than solid wire running short circuit.
The problem with short circuit MIG, particularly small machines, is that you can lay down a beautiful bead on just about anything, and.if it wasn't done properly, turn around and Peel that weld right off with a chisel. Welding through mill scale is a HUGE no-no with MIG.
The majority of commercial heavy manufacturing is done using What's called Spray Transfer of Pulsed Spray Transfer MIG using solid or metal cored wire and a blend of 98% argon, 2% oxygen or something thereabouts. Arc voltages are usually in the 30+ volt range, and wire feed rates like you wouldn't believe. (Both way beyond the capacity of a normal consumer grade or light commercial machine). In fact, the AWS does not recognize short circuit MIG as an acceptable process for structural welds. Flux core and Spray Transfer MIG are both acceptable processes, given the proper equipment and application.
But Yes, a Miller 211 will be a good, capable machine for most things on a rig, from body work to bumpers (but not roll cages).