Just compared the DualPro to the Spigen Slim Armor.
The DualPro has a VERY thin lip, but it's taller (by 1mm) than the Spigen, which has a lip about 3/4 as thick as the Commuter. The DualPro also has a thinner back than either the Commuter for the G2 I played with in store or the Spigen. The silicone is thinner on all sides, and is a softer, stickier rubber than either of the other two. But the plastic on the Commuter and the Spigen is not the soft-touch, rubber-coated type of the DualPro. That is a thin, but grippy case. It's also shorter than either the Commuter or Spigen.
But it's still bulkier than the QuickWindow case, and feels about as protective - which means it wouldn't be good for more than 20-30cm falls. The Commuter is the thickest and widest of the three, but has the most protection with its firm, thick silicone and port covers, plus a sturdy plastic shell and tall lip. The Spigen is shorter, thinner, but has little face protection due to its short lip. But the very firm TPU feels like it can handle a few bumps, as did similar TPU cases for my iPod Touch. Plus it has an okay grip, if not as good as the Incipio Dualpro. The DualPro is the thinnest two-part silicone case with a plastic frame I know of. It covers the corners and sides better than the official QuickWindow case, while being almost the same size. That is, IMO, also its weakness. It doesn't seem much better then the Feather, which has a thicker plastic shell that's the same width as the soft silicone here, and which also covers part of the top and bottom.
Still, nothing beats trying the cases yourself and seeing if one suits you better than the others.