There are a couple of threads around here on this product.
I would be concerned about reduced flight time and wind loading. I would also wonder how useful these may be in a fall from any significant altitude (probably not much).
Yes they actually charge $20 more for 2 red 2 white versus 4 white..I do a lot of flying around marshes so this is very interesting to me. The FAQ says it reduces flight time 30% which would roughly be 5 minutes on a normal 18 minute flight
I have been watching them (water stryder) since they were announce. Nice idea but seems a bit pricey. I have been using $0.99 swim noodles which I cut and wrap a tie around. Much more economical. Will wait for price to come down.