I bought the small red model. It worked fine the first time I used it in mild conditions.
I tried it this weekend in sustained 20 mph wind and 2.5 ft waves and didn't have the same luck. First off, I had a shackle on the anchor and a spring hook on the end of my anchor rope. This is a no no especially with the small model. It only weighs 230g and the shackle/snap weighs 80g. Hooked straight to the anchor that weight tends to pull it over on its side preventing it from digging in properly. Using a section of rope tied directly to the anchor before adding a shackle, snap or chain will alleviate this problem (Kinda like the instructions say to do, doh
Even after it got a grip this weekend, it let me creep along and broke loose altogether once (maybe due to the above configuration it never got a good grip?). After discussing it with Jon Cooper @ Cooper Anchors, given the weight of the loaded TI and the amount of surface it presents to the wind and wave to be pushed on, I am trading this anchor in for the blue 1 Kg model. I read somewhere that the red had been recommended for a TI but the red is intended for a canoe or kayak - the blue for PWC. A loaded TI is much closer to a PWC in weight and has a lot more surface to be pushed on by wind and wave so the blue is probably the correct choice unless you are just going to use it in mild conditions.
Kudos to Cooper Anchor for their outstanding customer support