I've been playing these and Ultex Jazz III's for a long time now, and I'm very happy I discovered them. This pick is really precise, while being a little bit thinner than a regular Jazz III. Ultex is stiffer than nylon, so this pick has pretty much the feel of a much thicker nylon pick, while still retaining an actually thin profile, which contributes to a cello-like attack and sound. Not the best pick if you're heavily into pick tapping a la Satriani, but other than this I can't come up with any major negatives.
The pick is translucent, which makes it a real pain to locate if you drop it. However, all guitarists know that once a pick is dropped it fades from existence and no longer exists in this physical universe.