After reading this thread for the first time in several months, I have to chime in and break it down. It's hard to say which is the BETTER album between the two since "better" is so subjective and depends on the listener's tastes and preferences.
All Eyez on Me, due to its rushed nature and Pac's stage in his development during its recording, is far from Pac's best work. However, it is still a classic album, still being played up to date on a regular basis around the world. Its appeal was its numerous club hits (All Bout U, How Do U Want It, California Love), cruising songs (Ambitionz az a Ridah, 2 of Amerikaz Most Wanted, No More Pain, Can't C Me), and raw emotion (Only God Can Judge Me, I Ain't Mad at Cha, Holla at Me). It will always be more bumpable and more hardcore in comparison to Life after Death. However, the album is just so hollow and directionless. Although it had a few gems, too much of the album was typical rap with Pac less willing to explore his boundaries as an emcee.
Life after Death, on the other hand, was all of Biggie's energy poured into just under two hours of music. It seemed to have just the right guest appearances, good beats, and the proper blend of different types of songs that various groups would find appealing. Biggie was more willing to experiment with different styles, as seen on tracks like Notorious Thugs and Playa Hater. It's hard to criticize the album from a hip-hop standpoint, especially since it was shortly before Biggie's death, when his skills were at their best.
What does all this mean? It means that in my opinion, Life after Death is a more complete album, but I still prefer listening to All Eyez on Me anyday, just like the majority. This is why we still hear tracks from All Eyez on Me in clubs, on the radio, bumping in cars, etc. Just this past weekend, I was at Tao (currently the best club in Las Vegas, located in the Venetian) and no song made people go crazier than California Love did. I hardly ever hear songs from Life after Death playing anywhere other than on my computer. So basically while Life after Death is the "better" album, All Eyez on Me STILL wins.
The Makaveli album would've been a more suitable comparison, but that's a whole other topic that has already been discussed time and time again.