Right, I've taken delivery of the new Brooks B17 Imperial saddles and I've installed mine on the VeloTron to start the breaking-in process before the Rhine Cycle Route ride, I used the saddle for the first time tonight for 70 minutes.
I was a bit surprised to find that unlike any other saddle I have ever used I found this one most comfortable with the saddle nose raised very slightly. I'd read mixed stories about these saddles with opinions ranging from folks raving about their comfort to people thinking they were only one step down from sitting on log splitter!
Initially with the saddle perfectly level when sitting up in a usual "touring" posture I felt very strongly that I was sliding forwards off the saddle and there was more weight on my arms than I am used to. With the nose tilted up slightly this "sliding forward" sensation stopped and things were much better.
In the past I have found that saddles tend to press on my sciatic nerve near the ischial tuberosity and during my first use of the Brooks B17 Imperial that wasn't problem at all. The saddle feels firm as I'd expected, being unpadded, but I would go so far as to say on the first ride that I found it relatively comfortable. Based on today's short indoor session (which tend to be more uncomfortable than outdoor riding) I am very encouraged by things, even before the saddle is broken in at all. I can already see on the saddle a couple of very slight depressions where my weight is being applied so that is encouraging.
However, one serious concern I have is with the overall geometry and "symmetry", or lack thereof, of the saddle. Looking at it directly from the front (see below) this brand new saddle appears to me to be out of "true". Lorena's saddle is the same though it is slightly less marked. I am concerned that this will get worse over time and in fact the upper part of the saddle to the LHS of the cutout already looks slightly lower than the RHS after a single use, the saddle upper just appears generally lower on the LHS. I'm going to contact Brooks about this and I'll report back when they have looked at the photograph.