Why question only for AGP users? If anything you should ask everyone to try to get an unbiased opinion because some users might be too inclined to agree with you or disagree with you. Anyway, it really depends on two things to make this a worthwhile purchase, the first one is pricing, as long as it's hovering around $220-240 it's not that bad. Second one and more important is what type of system do you have? If you have a good S939 X2 4200+, 2GB of DDR400 ram, good mobo, but stuck with AGP 8x then in my opinion it IS worthwhile buying it.
To sum it up, depending on the pricing of the card itself and how good is your AGP system then it is worth buying, if you don't have good CPU/Memory or if the card starts soaring around the $270-300 arena then it isn't that good.