I have both the Showers Pass Club Pro and Double Century. I used the Club Pro on a ride last weekend that was 4 hours of nonstop rain and wind. My gear underneath was wet by the end, but that may have been partly because I was not using the hood. The Club Pro's smaller pit zips are easier to access than the DC's, but also don't ventilate as well.

The best thing about the DC to me is that it is the lightest of the SP jackets, and the easiest to compress down to fit in a pocket or bar bag. All the SP jackets have a huge back vent, so you can open the cuffs to get flow-through ventilation. The DC offers excellent protection in a package that weighs next to nothing.

I haven't tried any of PI's Barrier line. A couple of years ago I had a PI Attack that was worthless (poor ventilation and the zipper failed after a few rides), so I'm a bit skeptical.