The 2000 can be a nice machine, not a whole lot of performance difference between a 4000 when both have a good accelerator and Zorro gfx card. No reason not to get it if the price is reasonable.
However, the A4000 does make a better computer to upgrade. The Zorro bus is much faster (at least 3x), there are more upgrades available (PCI busboards, PPC acclerators) and you'll probably want your main machine to have AGA.
Having an expanded A2000 and A1200 here on the desk, I'm starting to think replacing them both with an A4000 is the way to go.
