I am doing a competitive report for a friend of mine, and would like to get a clear report on the number of pages of a competitor's website.
What Joe said

To add to that, I'm not sure what kind of competitive insight that would give you.
First, the number indexed pages for a site is more interesting to me than the number of pages on a site. I'm not competing against pages which aren't indexed... For most sites the rough estimate you can arrive at by looking at the number of pages indexed is "good enough".
Second, unless you're comparing product sites and want to be able to say "you sell 10 products and he probably sells around 100 products on his site" -- what good does the information do you?
Which leads me to my third point; what are you comparing? By comparing straight numbers you're more than likely comparing apples with genetically manipulated turkeys. Because the fact is that your friend's hugely popular article "On The Art Of Growing Grass In A Coffee Cup" might bring in more traffic, more links, more conversions than 100 crappy or less popular articles on the competitor's site.
This is true even when you do compare 1-on-1. The fact that 2 sites each list the same 100 items means nothing. It is a quantitative measure. What you are interested in is the quality of each of those pages. How solid is the provided information? How juicy are the descriptions? How effective is upsell and cross-sell handled? How are non-buyers lead to other items they might buy? How does the pure ecstatic almost stupefying joy of using your site stack up to using theirs?
Competition is in quality and service more than in absolute numbers.