I would go with the Nyclads. I don't know about the Hydrashocks, but I know the Nyclads have a good track record in actual shootings. I currently carry Short-Barrel Gold Dots in my 642, but I've carried Nyclads before and never felt like I was "undergunned."

I also think 130gr FMJ makes a great practice round when carrying Nyclads for self-defense.

The most important thing, though, is to see which one you shoot better. I'd suggest getting a box of each and doing a side-by-side comparison at the range. The one you shoot better is the best choice for self-defense. But if you shoot them the same, go with the Nyclads.