The following comparison shows how the ports are formed. The cast brass and cast stainless steel have the smallest burrs -- by far. This will mean less chaos in the gas flow, fewer trapped particulate matter in the burner and a cleaner burning grill.

Why is port formation important? Several reasons. If the hole is punched into a sheet metal burner, it leaves a large tab inside the burner that will cause more chaos while burning. It is more apt to hold trapped food particles and grease, and is therefore more likely to burn through. (Note the Alfresco burner photo below.)

Molded ports in cast burners seem like they would be a good idea, but there is considerable difficulty in making them uniform. Thus, it is quicker and less expensive to drill.

Drilled ports are the most uniform and the most precisely placed. They tend to leave a burr on the inside of the burner, which is more noticeable (oddly enough) in a sheet metal burner. Cast burners tend to have smaller burrs.

Fire Magic: Drilled
Notice the lack of extensive burring, allowing for a smooth flow of gas. Cast stainless leaves few, if any, burrs when drilled. This burner has a lifetime warranty, including against rust and burn-through. Notice the placement of the ports: on the side, safely below the ridge. This placement will help prevent grease from dripping into the burner, minimizing the possibility of grease entering the burner.

Lynx: Drilled
Notice the lack of extensive burring, allowing for a smooth flow of gas. Cast brass is similar to cast stainless steel when drilled, leaving few, if any, burrs. This burner carries a lifetime warranty, including against rust and burn-through. It is also interesting to note that Lynx does not offer a replacement burner for any of their grills: simply, you'll never need one. Orifice placement is not as good with this burner as with the Fire Magic, but when you consider that you'll never replace this burner, it probably doesn't matter all that much.

Alfresco: Punched
Punched ports like these create substantial ledges where carbon particles and moisture can collect and foster burn-through. This burner has a limited lifetime warranty that only covers manufacturer's defect. With this design, this burner will burn through, and faster than most other burners on the market. Further, notice the placement of the ports: at 10 o'clock and 2 o'clock; if any grease were to drip onto this burner, it is almost guaranteed to enter these ports, thereby compounding the rust and burn-through issue.

DCS: Drilled
At least DCS drills burner ports. The burrs, however, are substantial when compared to cast stainless steel, and these will also collect particulates and moisture, which will foster burn-through. This burner also has a limited lifetime warranty that covers manufacturer's defects only, not rust or burn-through. This burner has a thicker steel than the Alfresco, but it also has a serious design flaw: the ports are drilled directly on top. If grease were to drip on this burner, it is guaranteed to enter the burner, compounding the rust and burn-through issue!