I have owned all models except for A3000T, so I can't speak to that model.
IMO the A2000 & A1200 were the best models. The 2000 because of its expandability and reliability - a beast of a machine, the 1200 because of its price point (after its initial release cost was lowered). You got AGA and soon after the ability to expand in many ways if you wanted.
The desktop A3000s and A4000s - they were nice, but weren't much of a departure from standard Amiga fare, really, other than the bus speed / processor slot architecture.
I had an A1200T/blizz060/ppc in a tower - was only zorro II, but I ran many of the same things comparably fast in relation to A3000/A4000. Only thing that made it choke was that Picasso IV wanted more bus.
Even if you look at it from a Toaster standpoint - The A2000 sort of wins as the toaster 4000 wasn't that much of a different beast than toaster 2.0/3.x or what not. Essentially a video switcher + effects. AGA aside, to me, you're basically in the same video land with the Toaster 2000 + some 030 or above processor.
Although the A3k and a4k offered easier access to graphics enhancements, 24bit was becoming commonplace around that time, and although Amiga had the upper hand with great gfx/paint software (TVpaint, many others), it was easy to see even as a user at the time that RTG and graphics addons for the amiga was a dead end.
