Good question Nick. My choice would always be for an original, well kept example.
I started searching for one of those and as much as I wanted an early chassis, I was adamant I wasn't in the game of collecting, speculating or investing in cars so the numbers, although important, were not going to dictate my decision. I passed on #86 & #63 because I firmly believed that originality in a drivable condition is more important than a number. I also wanted a car that I could use immediately (I started searching in Jul 2013) and not one I would have to rebuild over 7 years... until #19 was dangled in front of me like a mouldy carrot and I took a bite.
What can you do huh?