I've got both the DODOcase and the Portenzo (non-stylus version), so here's a quick overview of the two...
The Portenzo is very slightly wider maybe a 1/10 of an inch wider than the DODOcase. Personally I can't tell much difference in the weight between the two. When I spoke to Darin at Portenzo prior to buying the case, he mentioned that the stylus version is about 1/8 inch wider than the non-stylus version with the weight difference being negligible.
As for the DODOcase quality... I really liked the DODOcase, but had a few issues. First, although I fixed the peeling rubber corner issue with some superglue, it came back a few times and the slight exposed adhesive from the peeling attracted "gunk" which being a bit of a perfectionist drove me crazy. Second, on the inside of the DODOCase where the bottom "hinge" closest to the bamboo frame is located, the liner seemed to separate from the case just a bit. Combined with noticeable wearing/thinning of the hinge itself, I was concerned about the durability of the DODcase. By the way, I'm super-careful with my iPad/case so I highly doubt than any of this is "abuse-related." Finally, the cover on the DODOcase doesn't fold back completely. When folded, you still have a approx. 1/2 inch thich "spine" which may bother some people. It wasn't much of an issue for me, but your experience may differ.
On the Portenzo, the first thing I noticed was that it felt really well made. No peeling, obvious attention to detail from the smooth bamboo finishing to the mitred edges to the system to hold the pad in place. All very nice. In fact, I held the two cases next to each other to compare and noticed which I hadn't before that many of the bevels/cutouts on the DODOcase weren't even and were a bit ragged looking. Not so on the Portenzo. Again, you might not (I didn't) notice this on the DODOcase unless directly comparing or looking for it, but it's quite noticeable side-by-side. The liner of the Portenzo also seems to be very well-bonded to the case itself I have no worries about it separating as I noticed on the DODO. Additionally, the cover on the Portenzo folds flat against the back when open vs. the DODO which has that 1/2 spine width. I'm not sure how I feel about this as the result is that when in "typing mode" (i.e. folded into a triangular shape to prop it up) the DODOcase is more stable than the Portenzo.
To summarize, although l like both cases I personally will be sticking with the Portenzo. To me it feels more polished, has more attention to detail, and feels a bit more durable.