I’ve used a pretty cheap on (Duxtop or something like that) with a 6-8" heating coil. It worked fine on a well-conducting pan - 12" triple layer stainless-aluminum-stainless (like All-Clad, but a cheap version for restaurant use). It also did great with a 10" carbon steel pan. But I wasn’t doing anything that required maximum heat across the width of the pan. I think that’s a shortcoming for sure.
There are also reports of poor performance with larger cast iron pans, which makes sense - they’re not great heat conductors. So I think in part at least it depends on your cookware and what you’re cooking. Boil/simmer/fry in a larger highly conductive pan will likely be fine. Sear in a larger less-conductive pan maybe not so much.
I’ve used a pretty cheap on (Duxtop or something like that) with a 6-8" heating coil. It worked fine on a well-conducting pan - 12" triple layer stainless-aluminum-stainless (like All-Clad, but a cheap version for restaurant use). It also did great with a 10" carbon steel pan. But I wasn’t doing anything that required maximum heat across the width of the pan. I think that’s a shortcoming for sure.
There are also reports of poor performance with larger cast iron pans, which makes sense - they’re not great heat conductors. So I think in part at least it depends on your cookware and what you’re cooking. Boil/simmer/fry in a larger highly conductive pan will likely be fine. Sear in a larger less-conductive pan maybe not so much.