i'd go with performance as the main criteria. when looking at descriptions, if you see a very good the sound is usually acceptable. there is enough stuff out there in that category to keep you going for a real long time. anything below that its not as worth the effort. of course, the standards change with age of recording. with me, what i'll listen to off of the 1969 & 1972 tours differs from what i'll listen to off of say, the 2003 tour. another factor for me is if i was physically at the show. sentimental value. i've really gotten into it in the last year. there is so much good stuff out there for the stones & many of my other favorite bands. its like a maze. you find one source that leads to another source & so on. check out sugarmegs.org rolling stones (& jeff beck) section. you will blow your mind! have fun!