I am using these on my Martin HD28, as I was finding the standard 12's a bit stiff and wearying to play. Notes weren't sustaining as they should to my ears. These sound great, but have a noticeably lower tension, which I love. I'm able to get some more left hand nuance, as the strings have more give and single note lines /spread voicings are possible in a way that they weren't before. Great for fingerpicking too.

Due to recent shortages in Plectrum strings I have had to look for a similar Low Tension string for a Vintage guitar with no truss rod. A modified '63 Yamaha No.10 all wood.
I have found the Optima's to be a great replacement as they have a soft feel and good mid to high range tones. As the guitar has a lot of bass, it was good to get a little more brightness down low with the thinner E, A strings. My only thought is the Optima's are slightly noisy on the wound strings.
The guitar has settled into them nicely, and they are showing little to no signs of being played are several weeks of daily playing as I have experienced a lot of finger marks on the Plectrum bass strings.
All said and done, I am happy to stay with the Optima VintageFlex Acoustic strings.