No, 16>8 in challenge and difficulty. Lighter DPS check, harder tanking and healing. Much more emphasis on group coordination, group availability, raid damage and pride. I say pride because there is LITERALLY NO REASON TO DO 16 MAN OVER 8. We don't get anything more other than the pride from killing something on the hardest difficulty setting.
8>16 in popularity and availability. Hard as **** DPS check, Light tanking and healing. Much more emphasis on group composition and synergy. I like 8 man because its about the individual players performance over the group performance so everyone is taking much more responsibility upon themselves. If it was easy to get 16 individuals on the same page as it is in 8 man. 16 man content would be widely more popular.