IMHO the A 3000 T and A 4000 T were the 'flagship' Amiga models.
Plenty of expansion, the A 4000 T uses an AT PSU, and basically an AT case, with AT style motherboard.
The case of the A 4000 T is 1mm thick pressed _steel_, A2000's are made of different materials depending on the year of manufacture.
Trust me. I have an A2000(the made in germany one), I once owned a B2000, and the B2000 was technically superiour, but the build quality was slightly worse IMO, but still very good.
Expansion is important, to me it's more important than AGA, so IMHO having Zoro slots & drive bays are better than better graphics.
Also remember that the A3000, A3000UX, A3000T, A4000, A4000T, A1200, & CDTV(have I missed any?) all have 32-bit data busses! They are all much faster than an A2000 when accessing the motherboards bus.
The A2000 can have improved CPU cards, but even the A1200 can get better CPUs available for it, and even PCI slots. It is potentialy(heck, even by default) much faster than the A2000.
Being made of steel the A4000T will last - for a long time.
And whos A1200 has broken down just from age or ordinary use anyway?