Oct 20th 2010 3:44PM Yes mongoose is preferred (at level 80).
From Aldriana on EJ"
"Berserking and Mongoose have equal uptime. Hence, the comparison is 400 AP vs 120 agi and 30 haste rating (which is what Mongoose now gives). Pulling (say) the Assassination EP values, we have 120 * 2.8 + 30 * 2.2 = 336 + 66 = 402 EP for the Mongoose proc. Plus one raises your defensive stats while the other lowers them. That is: they're very very close, but Mongoose is currently looking slightly better."