Pac by far. And I like 50.
Pac was just too much of an impactful and talented poet and lyricist to be compared to 50. Plus, Pac was also a better technical rapper and had a much stronger mic presence. Discography wise, Pac has a 3-Peat while 50 only has one album deemed a true classic even though you'll find some people who retroactively praise the Massacre.
In a nutshell, the criticisms that the Booth give Pac apply more to to 50 when they claim that Pac was all about rapping about the thug life. 50 largely rapped about the streets and how hard we has while also touching on other derivative topics like clubs, selling drugs, being a "thug with a heart", and his material possessions.
Granted, 50 has a lot deep songs too(more than people give him credit for) but many of them are just surface level whereas Pac has whole songs breaking down society, socially conscious topics, his state of mind, his relationships with with friends/family, his life, etc. on a much deeper level.
It's just apples and oranges. 50 is legendary as an icon and a mixtape king while Pac is far closer to GOAT status and having lyrics and songs that will be studied "until the end of time."(Intentional Pun.)