It just depends on what kind of condition your paint is in. In my experience the Ultimate Compound is a very good mid level polish which will handle everything short of extreme damage or wetsanding repair. There isn't always a reason to use more than one product when correcting the paint. I've done several cars with nothing but Ultimate Compound and then a sealant, so it just depends.
I haven't ever used that autoscrub product. Until you mentioned it, I hadn't ever heard of it. However, after looking it up I can tell you that I won't ever be trying it. I am 100% against using a machine for the clay bar step and I avoid products that are designed for that or recommend a machine in any way. The process is pretty dang simple as it is, but I believe strongly it having your hands on the paint so you can ensure you are doing it right.
The biggest problem I have with machines is that I feel they just move too fast. I worry that they are just knocking the tops off the contamination that is embeded in your paint and not really removing it. Now if I were just removing overspray then perhaps I would look into something like this, but for the annual clay job that my vehicles get I want to know that I'm pulling contamination out of the paint and rolling it back into the clay so it isn't doing any further damage. I don't like the idea of all the contamination on your car to be right on the surface of your clay.
Anyway, I didn't mean for that to become a rant against a product I've never used. I just don't think clay bars are broken and the process I use works great for me, so I don't see a reason to change it up. I'll keep an eye on that one though and see what others have to say about it on some of the dedicated detailing forums out there. It wouldn't be the first time I've disregarded a product at first but finally came around to it later after all the reviews were in.