I have, over the past couple decades, used several different types of burners.
Initially, I was making Ron Reil type side arm burners (atmospheric) with various plumbing fixtures. I was using mig tips that must point straight down the burner tube. I found this alignment difficult to accomplish until I started using a lathe to drill holes to ensure proper alignment.
For a while, I experimented with commercial and home made ribbon burners (this was when I was trying to make a quiet forge to use while making videos).
I always came back to atmospheric burners. They are less expensive, easy to make and meet my forging needs.
One year at Quad States, I saw a demonstration where a very simple atmospheric burner was used. With modifications, it could be made easily using machine tools that most, if not all, blacksmiths would have (metal band saw, drill press and belt sander).
I developed a simple process to build it and made a YouTube video so others could make them.
Watch the YouTube video on the left.... This burner should heat a well lined forge (up to 300 cubic inches of burn chamber) to welding heat.
If you build this burner and have problems with it running well... Increase the mig tip size to .030 or .035