I have a Presidio Ultra and the Mini version as well. I like both and I prefer the plastic grips of the Ultras to the aluminum handles on the more expensive Presidio. I'm just not a fan of metal handles on my knives. The 440C steel is an old reliable. Easy to sharpen, easy to keep sharp and it holds an edge fine. Other steels will hold an edge longer under the same circumstances but 440C is a good utilitarian blade steel and can take a screamin' sharp edge. I don't have any experience with the Rift.
You can sharpen any knife with your Sharpmaker, no matter what steel is used. If you want to reprofile the blade or sharpen a damaged edge, get the diamond rods. But you can do a good job with just the medium and fine rods, it will just take longer.