I now own the Santa Ana, and have demoed the Samba, Nemesis, and the Savory 7 (not the Star). Keep in mind I demoed the Samba and Savory in powder, the Nemesis on hardpack, and I've only skied the Santa Ana on hardpack early season conditions. Here's a quick comparison from my experiences:
Santa Ana is the softest of the three, but the softness does not take away from the stability of this ski. It just adds to the playfulness. I agree with bounceswoosh, I had absolutely no problem holding an edge with these skis.
The Samba was a great balance for an all-mountain, freeride ski. I can't speak for how well, or badly this held an edge, it was all powder (24+ inches) when I tried it. Although it was not the "ideal" powder ski, I think it did pretty well. I'm hoping to get out on these again in the future, as I walked away from the demo last winter with these as my favorite of the day.
The Nemesis I found to be the stiffest of these skis, and for me the least fun. I enjoy a very playful ski and this one just didn't have "it", whatever "it" is. I felt like it was stuck in an awkward place between being an all-mountain do-it-all ski, and a wider powder friendly ski. It held an edge great on ice, but took a lot to get it up on edge to make a carve. A more aggressive skier would probably have more fun than I did on it.
The Savory 7, I also demoed in powder. For me, it didn't have enough float, I would love to try the Star 7 at some point in similar snow conditions. I found it skied more like a carver, but had some properties to be playful and the width to cut thru chop easily.
You have not skied the Santa Ana in powder yet? I'm surprised to hear the Savory 7 didn't have enough float!
The Sambas have very good edge grip on hard pack. Not my preferred thing to ski them on, but they do hold!
Santa Ana is considered a "freeride" ski. It's in the same category as the Star 7, but that's not to say that they will ski the same. I would image the Star 7 is closer to Santa Ana's big sister the La Nina.
For your reference, I'm 5'5" and approx. 135lbs, I ski the 169 and have been very happy with it thus far.