We had a Babies 'R Us brand fan that worked pretty well, but by the time we went to WDW DD was 6mo and she was grabbing the fan, pulling it off and throwing it. She ended up breaking the fan cage just a little, but enough to get her finger into. So that was the end of the fan. At the end of the day, I think it made zero difference to her.
Before we went to WDW we had only used the fan on a Bob stroller and she couldn't reach it, but at Disney we were using a Chicco Liteway (which is awesome for Disney) and it didn't have a good place to clip the fan that she couldn't reach.