The funny thing is while coding that stuff the bigger problems were financial and the enormous amount of cruft that is the web. The actual search engine wasn't that hard at all.
But I think that once you have enough customers the cost of 'crawling' goes down for every new customer you sign up because you only need to crawl a page once and you can sell the crawled result to many customers. Or do I misread your model and is every page crawled over and over again for every user ?
Could you define "good"?)