Rivet vs. Selle An-Atomica--how much difference?

[Jolt]

I suppose I should update this thread myself...I ended up deciding to go with a Brooks Cambium C17, with the cutout. Just got back from a 4-day tour that included a couple of 45-mile days (I know that doesn't sound like much, but this was my first tour and I was carrying all my gear) and no issues other than sore sit bones since that saddle is firmer than the Anatomica was...I think this one is a keeper. It appears that I will even be able to ride it without padded shorts, which is great. It is a lot more T-shaped than the Anatomica and that made a big difference for me in addition to the cutout being shaped better.