First, I think all the machines are overpriced.
Until recently, there weren't many new machines that I thought were as good as many of the B/W games in almost every category (theme implementation, art, humor, sound content and toys). Even B/C titles like Judge Dredd, Shadow, Congo, Demolition Man, etc..
A few areas where I think the newer games have exceeded the B/W titles are in rule complexity, lighting effects, sound quality and display.
So to me, if a full featured premium at 6.5k is priced right, then many of the B/W titles are underpriced. Until Iron Maiden, the Pros looked woefully barren compared to a B/W you could get for a lower price.
I find it ironic that many people are gravitating to the games with simple rules and layout, challenging gameplay and shorter ball times like TNA, yet dismiss the older B/W games as not being deep enough.
People want new, but like a house that's in good condition after 50 years, I'm more confident in the robustness and repair-ability of the older machines in a home environment than I am the newer ones.
Edit: You can tell from my collection I'm somewhat biased.