I had an HDR Senior Pro and I liked it alot, it was a bit slippery but comfy. My issue with it was that my QH out grew it. I had to trade it for a wider saddle. A friend of mine has the cheaper saddle which is the one you are looking at, and I actually like it better. It is not slick like the one I had and it has held up really well for her.
I have the Rivella, soon to be upgraded to a Devrel Deauville, which I really like, but I've heard only bad things about the club.. To be honest, I've only heard good things about the HDRs that are french leather assembled in Argentina, which are the Rivellas and the Devrels. The Club, Advantage, and Pro lines are Argentinian leather.