Ok, so yesterday I managed to find some time to re-string my uke with the new test-sugar strings. The instrument in question is a spruce top concert KoAloha Opio. As per my previous message in this thread, that instrument had the old Sugar strings on it.
As others have noted, the strings do look different. They have a more milky appearance. To illustrate, here are three images; the first is the original Sugar, the second has the G and C strings replaced, and the final has all four replaced.
The new strings are slightly thicker. Not terribly so, but all four seem to be just a tad thicker. Here is a comparison of the C string, original on the left, new on the right.
Sound wise, my initial impression is that the new Sugars are a bit more mellow than the original. This isn't necessarily a bad thing. In fact on this particular instrument I think I like the tone of the new ones more than the old ones. The combination of the spruce top and the incredible chime-like original Sugars made this a bit too brash for me. The new Sugars seem to take just a tiny bit of the edge off. They are still fairly chime like, just not as pronounced as they were. That's the good news.
Now for the bad news. They still squeak a little. Not as much as the originals did (when they were brand new), but they do still squeak enough that I still find it annoying. They have only been on for one day, and I haven't had much time to play it. I am going to give it a few more days and more play time to see how it develops. To put things into perspective: when I put on my first set of Sugars, back when the first iteration had just been introduced, I took them off again in just under an hour. The squeak drove me absolutely insane. The new formulation has not quite driven me mad yet, and if the squeak fades some more, I think I will leave them on as I rather like how this instrument sounds with them, at least strummed.
(I should also note that I am a finger-pad picker, not a nail picker. I prefer the sound and the feel of playing this way.)