DR Strings VTA-13 Veritas Phosphor Bronze Round-Core Med 13-56

I've tried many brands and string types for my guitars and have landed on these for my 2018 Martin D-41 for the past 3 years. They are very comfortable to play and assume tuning stability much sooner than most other strings I've used on any acoustic guitar. The volume response and dynamics are easy to manage and can range from delicate and melodic to loud and responsive. I use the Mediums on my Martin and have tried both the Lights and Bluegrass sets on other guitars without any issues other than preferring 80/20's on my 3 of my 5 remaining guitars.

The longevity is very decent, falling 1/2 way between coated and uncoated strings for me. That lands me on about 5-1/2 months, which means they get played almost every day alternating every third week. I do change my strings on the early side. Usually when they begin to lose strength (guitar sounds stiff), become muffled and/or when they become a PITA to tune and stay tuned. The annoying new string noises are gone by day-3. The new string brightness sticks around for a week at the most. From there, it's an evenly sounding tone for 4+ months before quickly decaying after that.

Great strings!

I really like these strings, and highly recommend them. They sound great, they're loud when I want to play loud, they feel good to play, and they last. I play a Martin OM-28V with fiddles, banjos, mandolins, and accordions, frequently with no amplification. So the challenge is competing with their volume by using medium gauge strings, heavy pick, and strong pick attack. The bonus Xenon 1st & 2nd plain strings are full sounding and powerful, compared to any other plain string I've used--they do indeed make a big difference.
Please be aware that these are round core strings--NOT hexagonal core as stated in this description. Why does that matter?
-First of all, I think it's an advantage... I believe that this type of construction increases volume and tone because of more complete contact between the core and the windings.
=Secondly, it's important to note that with round core strings, you must not cut the excess string off before the instrument is tuned to pitch and you have the string end crimped by bending the end upwards in order to lock the core and windings in place (the string ends are crimped at the factory to prevent this). This step prevents the round core from slipping in the wound wrap, which could shorten its life or make it difficult to stay in tune. This precaution is stated inside the package.