I started with those foam clip-on bobber, and keep a good stock in my tackle box. I also added some spring bobbers to my rods this year. The dancing of the foam bobber can tell you if a predator is making your minnow go into 'evade' mode, the spring bobber gives away the slightest nibbles much more easily.
If I'm trying to hang to a specific regular depth, especially if I'm dead sticking, the float bobber all the way. Easy to see from a distance, entertaining to watch. If I'm targeting specific marks on the flasher, I like the spring bobber. Great when actively jigging, helps tell hits even on the fall, and helps compensate for the lack of sensitivity in cheaper rods.