Taeyeon has the most amount of #1 spots in the lists with 258, followed by Tiffany with 154, and Hyoyeon with 118.
I was looking at the SNSD Member Rankings thread on Soshified and I found this very interesting. The average Hyoyeon ranking is 6.54 (out of 9), which means of course that there are a lot of Sones are placing her in their bottom 3. However she’s still managed to get the third most #1 spots.
Okay that doesn’t sound too exciting really, but what it means is that Hyoyeon isn’t necessarily unpopular. It’s just that she has niche appeal. Her individual fanbase is higher than the majority of SNSD.