Hello!
Nah, I think the one at Shapeways is a little bit better of the two... To me it looks like the search engine has the tendency to append the whole inventory to the results of the search.
Plus, with such a wide subject range you have the problem, that when you keep your search generic - for example "1:72" - you get a ton of results and sorted according to some unclear rule. And when you narrow it down sharply - like "M110 engine bay" - you will most likely get no results - sometimes it's even in stock, but described somewhat differently - and then Shapeways just shows you the whole inventory.
This sucks, but this isn't so easy to get right - especially with such a huge database of products. You might say that the search feture is just as good as the designers are at describing their products.
In the end it still is a very cool internet enterprise!
Good luck with it and have a nice day
Paweł