For me, it came down to: A new, but lessor quality pen for ~$350 or an original but not new "51" that is a very high quality pen for ~ $100 for a nice pedestrian version. I went with the original and would every time. Now if they would have sold the 100 for around $35.00 - that would have encouraged me.
I always thought the 100's price was too high. That, and the reports of finish quality/performance problems kept me away. If it had sold around the $125 range, I might have bought one. Someday, I might be able to afford both a good 51 and a 100.