with a flux wire feed, its all about heat and wire feed. Both cant be really controlled with a pair of hi-lo switches. Plus the consumables are hit and miss. If you got good penetration, a grinder can make most flux welds look OK.
A grinder does not make you a welder, but a cheap machine is really hard to learn to weld on.
I bought a Holbert 140, for home use, for what it costs its reasonable, hook it up to a bottle, buy a bigger spool of wire for it.
I really like the Lincoln 225 they have at work, but man they are expensive.
