I don't entirely agree. I've indexed 6 millions of pages and 1,5 millions of images on Google (these are the serps it returns) in a couple of months. In no way absolutely I would have gotten such a speedy result from Yahoo or Bing. Bing in particular can be extremely stubborn to start indexing in absence of what it considers "authority links"
In decreasing "reactivity speed" order (fastest to slowest),
meant as ability to index fast when they want, this is my list:
Yahoo (rip, soon retired)
Yandex
Baidu
Bing
Ask
How do you manage to have 15 000 pages website ??
Do you generate pages with a script?? Are the pages any good?
I am working on one right now, I am trying to make it a very good quality, 100 pages ahh what a PAIN.
To get to the topic, I published my website in start of december, 80 pages then.
Yahoo indexd all pages, Some very good SERP.
Bing indexd 25 pages today
google indexd 50% pages, but no SERP.