The musical value is you'll have the best drum machine that was ever produced.
The thing is not only legendary for its sound, but also for the swing and especially for the workflow (super simple, straight forward, almost no hidden functions, etc).
The thing isn't exactly rare either, but most people who have one don't want to ever sell it again. So if somebody decides to sell it, they want their "emotional" values worth... if those are stupid prices or not... well, the market decides that (at the moment there is one on ebay for 2200 and people are bidding).
My friend paid more than 2000 francs years ago. I paid 2400 for mine (same seller is at 3300 now, you all know him). Some people still find one for 1500, but you gotta be patient and always looking.
If you offered me 2k cash AND an EMAX in exchange for my SP1200, i would still decline. It's not the same machine... maybe it sounds very similar, but it's not an SP1200 with all the little things that make it exactly that (and i would never butcher mine for the above rack mount mod (even if it looks like top quality)).
It's a legend.... it's THE LEGEND, period.

"It is no measure of health to be well adjusted to a profoundly sick society." - R. D. Laing