I don't so much mind fixing dents...

[VintageMusclecar]

Everything was wire-wheeled back to bare metal at least 1" back from the seams. (made for some interesting acrobatics trying to reach some of the areas with a 90° grinder lol)

Like I said, I'm pretty sure it's a combination of my less-than-mediocre welding skills paired with a less-than-stellar welder. I've done much nicer work with a better welder, so this is one of those instances where a quality tool makes for a better operator.

Even if I had a better welder, I'd still hate fixing rust.

Eric

[Schonyenko2]

I know everyone has a favorite, but I'm pretty happy with my Lincoln. I have both Lincoln welder, and plasma cutter. No issues with either of them. The Miller plasma cutter kept blowing circuit boards.
Butt welding is more difficult. Sometimes a copper block behind the seam helps control any bleed through.
Sometimes it's actually easier, quicker, and gives you a better finished product to replace an entire panel, than to fix a rusted area. Wheel lips are a good example.

[YENKO DEUCE REGISTRY]

Schoneye is right, I've also had good luck with my Lincoln welder - no complaints so far, except that I don't have a plasma cutter... yet!

I use a piece of stainless plate behind the two panels being welded, copper works equally as well.