I got a kick out of this tonight -- the GP-30 is one of my all-time favorite engines, and a quick real-time price comparison on eBay reveals the following: Williams - $200. Lionel - $500.
The Lionel version:
http://www.ebay.com/itm/LIONEL...;hash=item51a7e76e9e
The Williams version:
http://www.ebay.com/itm/WILLIA...;hash=item3f21d40abd
They both look like detailed units, they both likely pull a lot of cars, have lights/sounds/etc. But the price is where Lionel loses me, and fast. For $500, I can buy two of the Williams Geeps -- both of which Bachmann stands behind with a lifetime warranty -- and put the remaining $100 in the bank! True, the Williams units may lack "Legacy" and perhaps a few tiny plastic details, but this is an example of why Lionel gets crossed off my list virtually every time I'm in the market for a new engine these days. And as an investment, they're not worth $500 a pop. I'll wage if the original owner e-Bay's them at a later date, he/she will be lucky to recover half of that.