Alive is one of the greatest live rock albums ever done. When you take into account the technical shortcommings of the musicians and shoestring budget of the project this is a particularly astonishing fact. No disrespect to the members of Kiss (who at the time were producing some of the best straight up rock there was) or to Alive 2 but their first live album really set the bar so very few other bands have been able to approach.
Compare - for example - the first live Yes album with top notch caliber musicians at their most popular and Alive just has 100 times the energy and musical accessibility.
And this is coming from a hardcore Yes fan.