What is the best brand strings to use on a acoustic guitar?

It's a matter of taste really. Personally, I don't care one way or the other. But for the record, I once wrote a letter of compliment to D'addario, and they sent me a pack of strings, a booklet of helpful guitar tips, and a T-shirt. I very much appreciated it and now, as a thoroughly satisfied customer, I buy them whenever I see them.

My favorites are Elixir, John Pearse and DR. My second favorites (if you want something cheaper) would be Dean Markley or Martin.

i like elixirs, they sound so much better, for such a longer time.

This sometimes depends on the style of music you play but as a brand, Ernie Ball Acoustic strings are the best in general. They are easy to play and sound brilliant. I've put them on guitars I purchased used that didn't have Ernie Balls and the sound went from dull and dead to clear mellow ringing tones and bright overtones.

I use Ernie Ball Super Slinky Acoustic Phosphor Bronze strings for both live playing and studio work. I play mostly Alternative, Folk and Light Rock on my acoustic and this string is excellent for all three. I can afford to use any string but the $6 Ernie Ball is by far my favorite.

I have played, Elixer, GHS, D'Addario, Martin, and Dunlop strings over the years and I always quickly come back to Ernie Ball strings. They play easier, they sound better, and they are durable. The Ernie balls are technically superior for reasons having to do with "hex core plated wire" but I won't get all technical here. Suffice to say they are just years ahead of other competing strings.

I don't play professionally any longer but nearly all my friends who do use Ernie Ball strings on stage because the Ernie Ball RPS strings almost never break and they stay in tune indoors or out.

The bottom line is there are $3 to $30 strings out there. The $6 Ernie Ball strings are just better and it's cool that they are made in USA! Buy some and you will see. I don't work for Ernie Ball and I don't own stock. I just like to play and know a good set of strings can make all the difference.