Flux core sucks, fight me
. (unless you are building a bridge or welding a structure in a hurricane) Dual shield is really cool tech though. For most DIY guys a MIG with gas can make beautiful strong welds. Getting the machine and the operator setup correctly is worth it.
Yes Prep is another one I see not even amateurs fail at. I love my blast cabinet. It gets me clean bare metal with a quickness. Acid tanks are good for mild steel. Cleans off rust and mill scale well.
Love me some TIG, but its time consuming for somethings. Roll cages with TIG SUCKS. I tend to MIG tack exhaust systems, and carry them to the bench for finishing. (I only do stainless exhausts now).