As they say, it's hard to know what you want until you actually get a chance to see it and I had that chance a few weeks ago at the NYBG. I don't remember what section this particular garden was in but it was a stone walled garden very reminiscent of the one at Mamaroneck. I loved how this mix of green foliage created such an interesting range of color and texture especially in its location at the front of the beds and spilling over, and this was late into the season too.
The Watch Chain Crassula is probably the one I'm least interested in because its considered a tender perennial but the Sedum Rupestre is considered especially hardy and the Golden Poet's Jasmine is a terrific way to get that sharp color in the bed. The smaller leaves and sprawling habit I think is more suited in distributing the visual weight of this color which I find too much of can be a little jarring. I also love the bronze color of the newer growth.