Swan had a great good quality: he was able to adapt his style to the times.
When he began drawing Superman in 1953 with the SUPERMAN 3-D one shot, and during the whole Silver Age, he drawn with a classic style, without splash pages or various excesses. Then, he staied aboard during the Bronze Age, and changed his style: more dynamic, modern... But always polite (his faces were great... Every good character seemed an old friend). A few other artists could do the same, in my opinion.
I guess I'm not surprised to see some of my faves missing from your list, but I would have thought you'd at least include Alex Ross. I'm still on the fence about his Superman, but the consensus in the fan community seems to be that it's great. At the very least it's more famous than Jim Lee's.
It's not my fault! I couldn't add other options! I have put the "others" option, but the poll didn't insert it. Maybe can't we put more than 8 options?