With the GeForce3, NVIDIA implemented a variety of multisampling techniques to provide increased antialiasing performance. With multisampling, the graphics processing unit is aware that antialiasing is being used and carries with it the samples needed to generate a final pixel color. In other words, multisampling is done in hardware on the GeForce3.The discussion continues here. FiringSquad does a more traditional review with benchmarks.
Antialiasing is a subjective topic. Not only are there discussions on whether one should use antialiasing, but there are arguments on which type of antialiasing is preferred. We've polled forum members regarding image quality and antialiasing, as did Reverend's 3D Pulpit, and the responses were varied enough to conclude that there isn't always a right answer. In some cases, antialiasing can generate high quality images, but performance is so poor that it's not usable. On the other hand, performance can be improved by using a lesser quality of antialiasing but then image quality is compromised.