The 1000 is a collector's item already IMHO: it's where the amiga started, and throughout the whole of the history of the Amiga hardware it was the biggest hardware innovation in terms of redefining personal computing. I have one, I am using it often, and I have big plans for it ;-) .
The 4000 could and should have been much more. It needed to be much more for CBM to survive. It should have been AAA, it should have had a DSP, it should have moved the game on in the same way OCS did. it didn't. I'd bet that way more 4000s than 1000s were made, too.
That particular 4000 had broken keys and broken cosmetic bits on the main machine: it's not going to appeal to a collector. There's also the risk that the battery is knackered, and that the sound circuits have failed due to leaky caps. the sound on my 1000 is better than the sound on my 4000 :-)
Saying that, I think the 4000 was about right money wise, but the 1000 was too expensive. I about that for one that was boxed, mint, with manuals, with a Xebec hard drive and a Spirit inboard expansion!