Let's see.....
One has ever-increasing blinds which will require us to adjust our play accordingly. (with all kinds of intracies... ie. 3 & 4-betting vs. diff. stack sizes, 3bet shoving/stealing, etc. etc. etc. etc. Many, many things that will require knowledge on how to play varying stack sizes, quite often in the 35 to 50bb range).
Cashgame > typically ~100bb's+
Deepstacked poker where one needs to know how to play the pokerzz.
My online experience has been >> tournament play seems to attract a larger number of weak & newer players to the tables vs. cash. Anyone can win a tournament