I like the MPLs because of their rarity and their eye appeal, which includes the color and toning. That's pretty much how I value how much they are worth to me.
Sure, the prices of these have gone up a ton in just a few years, but the same can be said for many series. Just goes back to supply and demand of course, lots of folks want MPLs with stunning eye appeal and there just isn't many of them out there.
Also, I've read in other sources that the mintage on the '09 VDB was only 420, but that the higher number is the one most of the source documents refer to. Though the graded population of the VDB seems to better support the lower figure.
Some would think I paid alot for this one that I have that I got from Andy, but I think I got a bargain.