Very beautiful machine. Wow.
As for what it is 'worth', that is always a tough question. The fact is, you may find one cheaper, but the other fact is, could you commission someone to hand-make even just that coffin top for that price, never mind the rest of the machine? It is a personal decision, of course, as to whether you want to buy it. My observation is that these amazing machines are way under-valued, in general, and therefore we can often get them so cheaply, and we get funky ideas as to what things are 'worth; or not. As a thought exercise, put that Naumann handcrank on a table next to an entry level Janome Plastic Fantastic, and ask yourself which one is worth $150... ;-)