A mate of mine who was and is an excellent (a former top-10 nationwide) pool billiards player once said to me: 8ball is for the smarties, and 9ball is for the dummies.
I don´t know, but all forms of the eight balls seems to come down just how you handle the last few balls. Since it is so easy to make runs from the beginning. Just a very good players can keep it going and still bend and blend it when it comes down to the last few balls. That mate of mine certainly can do that, he is like a poetry in motion when on-song. Last time (previous summer) when we played properly I got beat something like 7-1 while playing eight ball, but immediately after that I beat him was it 8-3 or 8-4 when we played nine ball. Those were a very high quality games, that lad for example cleared from 1 to 9 with a minute with an effortless ease. And he certainly showed me how you really need to keep it going while playing eight ball, otherwise it is just useless when playing against the top-players.