For sheet metal repairs, Oxy Acetylene is by far the most versatile. I have stuck with it and my original supplier for a very long time, despite ever rising costs. There is very little price competition between national suppliers. Tried Mig, but this will only give good results on nice new clean metal, if you are just a casual user. It requires more skill and practice than the adverts would have you believe.
Most MIG Welds on vehicle body repairs I have seen are of the chicken shit surface finish, even from so called professionals, who cover their artwork with body filler. TIG seems to be halfway between, giving the convenience of electric welding with a much more controllable arc. I was fascinated to watch guys TIG weld stainless tubing, the arc was just like a candle flame, nice and soft with the metal pooling and moving easily into the joint. Very smooth welds, very little surface finishing required, but welding equipment relatively expensive for top brands.
Here in the UK, one downside to OxyAcetylene is that supply is in the hands of a few major players who make their money on gas bottle rental and fixed charges getting the bottles from the store. Also both bottles never run dry at the same time, so it is cheaper to swap both even though one still contains gas you have paid for. Meaning one service charge for two bottles, and a single journey to the depot. Oh yes, they will also charge you for an invoice, but crazily give you credit. In effect I am paying for the bad payers and the company's accounts department. Direct debit payments will avoid the invoice charge. I would always go for a cheaper cash on the nail deal, but there is no discount for prompt payment. With high charges I never have it delivered, for a couple of bottles it makes no economic sense for a small scale user like me. It really feels like money for nothing. Despite the well established British trading title, the company now has a strong European connection.
There are other suppliers for gases, with a business model without continuous bottle rental, but none of them seem to be able to supply acetylene.
Swarfy