I am interested in a Vintage Speedmaster - a pre moon ideally. This is for 2 reasons - I want something genuine which from what little I have read means getting something from approx 1965 the Pre-Professional 105.003 Ed White watch. There are other models - the 105.012 and 145.012, but the 105.003 is what I understand to be 'the grail watch'. The second reason is what attracted me to the Speedmaster is its link to Space exploration. I intend to wear the watch on a fairly regular basis - once a fortnight in an office environment so it shouldn't degrade.
I have found dealers selling these watches and would like the following help - what should I expect to pay for a pristine example and exactly why / how special / rare are these watches. I have found dealers in London with them for approx £3,500, while another has one for £7,000 and doesn't seem to be able to explain why his watch is so much more. I will grant him that his is in exquisite condition, but given part of the reason for my interest in a vintage watch is as a future investment - 10-20 years, I don't see why his is worth so much more. A brand new moonwatch in the Omega boutique is 'only' £2190, so I don't see why there is quite that margin of difference, especially when the dealer couldn't give any special reason.
Information about valuing / understanding the value would be most welcome. I am also considering a Montblanc Timewalker TwinFly, mainly because the design pleases me, but I don't want to dismiss the Speedmaster too early.