the 960t is generally better but if you OC both chips their performance should be similar. the 960t can be sometimes unlocked to a 6 core cpu but its not always possible and you might not have stable clock speeds when you do.
the 960t is 5% faster than the FX4100 at stock and about even once you OC both cpus to the max. In multi threading with the 4100 you can take an up to 30% increase in performance in some multithreaded applications.
Better is a point of view. He may prefer the Phenom II 960T, and it is a good processor, but the 4100 is better at multi thread applications and the difference is not worth the price difference to me. The 960T may get you a few more frames per second, but not enough to warrant the price difference. The 4100 still gets a bad rap from the initial release, but they are performing quite well now, and to me they even overclock better. You cannot lose out with either, but if I was you, I would get the 4100 now and save up for the Piledriver line that should be out later this year.