I was going to wait to comment on mine in another thread, but I guess if no one minds I'll piggyback off of larcklorn's thread.
I sent mine off Thursday, and got it back the next Thursday. I only rode Friday and today (Monday) to and from work (23 miles each way) - but so far I like it. He said it will take a couple tanks of gas to get it to settle in, and I can feel a difference with just 2 days worth of riding (about 100 miles). It is firmer yet cushy if that makes any sense. Like DownrangeFuture said a couple posts up, it feels more like an actual chair cushion. Moving around on the seat is no different then the original, there is no padding shift at all. I was a bit concerned there may be some movement as he uses a few different kinds of material, but the seat padding feels like it's one piece. I was going to take some pictures, but it looks just like it did when I sent it out so there was no point.
At first I wasn't sure how much I was going to like it over the other option I had considered (Top Sellerie), but so far I'm happy with my decision. One week from this Sunday I'll be on the bike pretty much all day, so that will be the real test. I am taking an ERC course - it's a 10 hour course and I have to ride about an hour and a half to get there. I'm looking forward to seeing how well the seat performs, but I'm not too worried judging from what I've experienced so far. I would recommend doing this if you want a better ride but don't want to spend the $450 for another seat.
I'll post back after my ERC course, should have about 550-600 miles on it by then.