After Luiz's comments I´ve realized I didn´t go into much detail about the photos. This is actually a very typical thing in the rural areas of Brazil. 2 guitar players start to improvise singing. One says something and the other "replies". It´s a very very nice thing to see.
Ah, that makes more sense now. The reason I didn't prefer the second photo was because the composition made me feel like the guitarists are separated from each other. I liked the third photo because it made me feel that they were more in unity.
Now that I know that it is a 'duel' the second photo is more appealing for me now.