Wheel reflectors, in my experience, usually buzz and eventually break off, but also look like the thoughtless hacks they are, and do nothing to enhance aesthetic appeal if they don't degrade it.

Yes they increase visibility, but with proper and sufficient active lighting (i.e. lights), I think wheel reflectors add nothing of consequence.

If you won't be lighted at night, then reflectivity is important. I'd go with 10Wheels and use reflective tape over hard plastic reflectors, though perhaps not as exuberantly! Check out Lightweights for products and ideas: Lightweights

Keep in mind that motion is attention-getting, and probably better for being seen than solid brightness, whether talking light mode or reflective accents. Specifically, I think pedal/shoe/leg reflectors are best, wheel reflectors less so due to "persistence of vision" effect, but that will depend on how much tape and riding speed.