The solo in "Beast and the Harlot" by Avenged Sevenfold stands out to me as a solo, and as a song in general, mainly because it isn't pure metal, and instead begins to take an example from classical music, especially in the chorus. It's not like one genre is better, but the blend of classical optomism with metal's pessimism, especially with its transition in the middle of the solo between both sides of the song. Mix that with a guitar soloist skill, and it can sound very unique and entertaining, especially in a string quartet version of the song that does the song even more justice than a song like it deserves, making it sound like an actual classical song.