you can fit like 6 3.5" devices in the 3000d and fans to keep everything cool! you have to get a little goofy with power splitters and make brackets to hold drives on top of each other but they all easily fit.
ethernet, or zorro scsi, and video card and sound card all fit nicely, and if you dont have a video card you can still hook it up to any vga monitor.
in just the past year here on amiga.org i have seen dozens of posts for people looking for scan doubler/flicker fixers for their 1200s and 4000s and i just kick back with my 3000 hooked up to a huge svga monitor.
having aga missing is big, granted, but playing on a stable flicker free crystal clear screen more than makes up for it. many games were released for aga and ocs/ecs and many newer games had rtg versions also esp. 3d games.
i guess this means you can put my vote with the 3000 especially since i sold my 1200 to buy one, 4000s are pretty pricey even now.
just my 2 cents
or like 6 or 7 cents :-D