I played the three Streamsong courses last week and Sand Valley's 1 1/2 in mid-October.
Based on what I had read, I was prepared to LOVE Streamsong Black. As it turned out, however, I left with reservations about it. To be clear, I think it is a very good course, and I am eager to play it again. Yet my initial take on the greens is that they may be over the edge...at least at the speeds they are currently kept.
I had the opportunity to ask Gil Hanse about the greens and how they fit with his notion of making a course "playable" for golfers of different abilities. I told him I thought they were very difficult even for relatively skilled players. Gil's response was interesting. He said the original intent was for the greens to be smaller, with most of the largest humps located OFF the green. After initial grown in, the decision was made to (greatly) expand the greens, putting large bumps and swales inside the green. All in all, putting the bumps inside the putting surface may have made the course "feel" more difficult. Three (and four!) putts are not uncommon, and somehow they feel even worse than a failure to get up and down from off the green.
Gil said that humps and bumps adjacent to the green pose an interesting challenge for skilled players. They are eager to get up and down, and the terrain forces them to make decisions about how best to cope with the terrain (club, trajectory, landing spot etc). Less skilled players, on the other hand, are not as worried about knocking the ball stiff. Therefore, they often take a putter and whack it over the hill somewhere on the putting surface. Not as complicated or as delicate. So humps and bumps off the green strike a nice balance: interesting and challenging for skilled players but not overwhelming for others.
Again, the speed of Black's greens is potentially as problematic as their configuration...especially given how exposed they are and the potential for significant wind on the site.
I found the greens on Streamsong Red and Blue to be plenty challenging and interesting without going over the limit. In the end, I preferred both Red and Blue to the Black course...perhaps with a slight overall edge to the Blue. But I only played each course once. After I have played each five times, my ranking could change completely. All three are excellent.
Sand Valley is less dramatic than the Streamsong courses yet very good. Indeed, I was struck at how visually intimidating Red was in places, not a feature I usually associate with Coore and Crenshaw. Sand Valley seems more similar to other C&C courses I have played (eg Bandon Trails, Dormie). Based on the nine holes I played on Mammoth Dunes, I think that will be the more dramatic of the Sand Valley courses.