I have recently tried the Martin Premium strings. I like them and would put them above many other strings I have tried. There is a bit of texture to them and a faint scratchiness in the sound, but it is not as prominent as some other strings and nowhere near the squeak some experienced with sugar strings. I don't really hear it except when doing some fingerpicking. So far, I don't find it a big problem. I'll see if I feel differently as time passes.
I like the feel of these strings. They have a nice flex, are not too stiff and feel good under my fingers. I find the sound to have a nice clarity and crispness, perhaps slightly fewer highs than fluorocarbon, with a little more mid range. To my ear that seems to give them a little more warmth and depth.
Sometimes fluorocarbon can seem a little edgy, thin or brittle sounding on some instruments, while some of the nylon based strings can seem a little dead. Some of the nylon or Aquila strings can feel a little thick under the fingers. On both counts I find these to be a nice middle ground. Intonation is good and they settled in very quickly. Initially they stretched a fair amount, but within a day I could play them with minimal tweaking.
While it is up to each player's taste and how it fits your instrument and style of playing, I would say that these are a great addition to the mass of strings out there and are well worth a try.