It depends on how you look at it, the Amplifier/B2 is Genesis, a true ground breaking concept for it's time, not without its short comings granted, and featured one of the most important innovations for rear suspension design, the "Horst link".
The B3 is an evolution, the original design was noted for being flexy in the rear, the B3 was a step forward in improving things slightly, the shorter shock meant the stays were shorter, still flexy though.
I'm biased, my '95 B3 has been with me since the tail end of '94 it was supplied by Kevin (one of the Cheviot Hillbillies) when he had just started his shop, I was expecting a B2, so was plesently supprised when a B3 arrived. Everyone said it would break, it hasn't and it's nearly 20 years old, still looks as good as the day i opend it's box and i still stare at it in the garage in amazement.
I really should get out more.
So, it really depends on what you like, the original masterpiece, or the improved refined (better) bike
Ride wise, there's not a lot in it.