I had always heard that the A1200 is a more stable, compatible machine. That the extra hardware in the A4000 pushes it further afield from the center of compatibility.
Is that not the case?
Now, back in the day, when the machines were new, I'd say the A4000 was by far the more stable of the machines. I owned an A1200 with expansions and an A4000/040 (later upgraded to 060), and my A4000 spanked my A1200 in so far as stability. The 4000 was a rock-solid bulldog that could run for days (or weeks) on end without a reboot. The 1200 might get a couple hours, if you were lucky.
And how bad _are_ the caps in the A4000? I've got a room full of computers...
Terrible. The only two Amigas I've had cap problems on were both A4000s. The 4000's also have the self-destructing SIMM sockets. (The only broken SIMM sockets I've seen [besides extreme neglect/impact/stupidity cases] have also been on A4000s.
Oddly enough I've never had the cap problems on my various 1200s, though several, including my current model have been plagued with the vertical flash syndrome.
Personally, I got rid of my big-box Amigas a few years ago, and I can't really say I miss the old hassles. Priorities change, and I'm happier with my 1200 with an 030 in the stock desktop wedge, nowadays. (Ironically, it's very similar to what my 1200 started out as back in the day, before I expanded it and sold the lot and bought the 4000.)