I have both machines (well in fact all but the tower models of all of the Amiga model lines).
The 1000 was the Amiga I wanted most but by the time I had finally saved up enough to get one the 500 was out and the 1000 was on the outs. Not considered as capable as the 500 because of the keyboard, only 256k for Kickstart, and limited to 512k chip RAM.
The 3000 is even more capable an Amiga than the 500/2000 were. Built in hard drive controller, added space internal for RAM, 2MB Chip RAM, 32bit bus for Zorro III, video slot, Space for two floppy drives, and the ultimate nowadays a built in Flicker fixer allowing it to connect to standard VGA monitors out of the box, accelerated. So for all around most flexable Amiga the 3000 wins (4000 edges it out a little having IDE and using SIMMs for RAM instead of ZIPs, and having AGA, but then is edged out a bit not having a flicker fixer). 3000 is also a LOT better built than the 1000, having a metal case aside from the front bezel, though the front of the case can be a detriment to adding the second floppy drive, not being able to use drives with a front faceplate as the 2000 and 4000 can and so needing to get the right models to line up with the slot. Add to that the ability to run Amiga Unix (if you really want to try to get it loaded up noadays and see what 'workstation class' was back then). 3000 has decent space for expansions internal which tend to be less expensive, and the casework is less likely to be damaged opening it to get those expansions inside than the plasticwork 1000.
The 3000 easily runs Amiga OS 2.0 and up, but to run below that is not easy. The 1000 runs 0.7 to 1.4 (yes, those non released versions included and easy to get if you know how nowadays) but not easily able to run 2.0 and up.
The 1000 is a plastic case with no brass insets for the screws to go into. They tap directly into the plastic meaning if you have to open the machine too many times, or even few times but overtignten the screw, you risk stripping the screw holes or cracking the screw hole posts. This is not just the case but also the screws holding on the front bezel. The 1000 has a reduced keyboard, though at the time of release it was all the keys, later keyboards on all Amigas have more and this can cause some games that need a lot of controls to be harder or not play on the 1000, flight SIMs come to mind. That said it has the sexy keyboard garage which gives the 1000 a lot of charm. It has only one expansion slot, and that is opposite laid out to the 500s making expansions harder to come by that fit properly. It also means you have to 'centepede' it along the desk if you add RAM, Hard drive controller, and other things to it. though this is the case I actually had more fun 'tricking out' my 1000 than any other Amiga. The Genlock that fits in the space under the back, the modem that attached to the side at a whopping 1200 baud, the sound samplers designed to sit in its joystick port (mimetics) or in its parallel port and made to stick out over the top of the back of the case for access from the machines front (the first Perfect Sound).
1000 also beats out the 3000 on pure nostalgia. It was the first, it was designed by the original Amiga crew, it has their signatures in the case. It plays those tones before loading kickstart that no other Amiga does.
So in short, 3000 is a very capable, and great 'daily driver' Amiga. It is on my desk and I use it to make floppies from ADFs, to copy floppies. I dont have to worry about a 1084 monitor blowing a flyback or whatever makes them die pitiful deaths followed by the anguished NOOOOOO from the Amiga owner who has to try to get a new one with the shipping costs generally more than the price, try to get it fixed in a land where CRTs are like dodo birds, or pay a lot for a flicker fixer. Hook up of hard drives and Opticals are easy, long as you can get your hands on the SCSI stuff.
The 1000 is on the back desk in the corner next to my Vic-20 and 128D. That, is 'the Amiga'.
You use the 3000. But while you're using it, the 1000 is the Amiga you're thinking about.
