cost I can't answer because it came forward from previous i box and it was configured differently than it is now.
I can create "reports" that I can get in excel, pdf or on the screen for example, I can have a drop down so they can select what they want, the select drop down can be dynamic in that it is built with the data from within, I can go and do filtering of the data, I can do graphs (bar, pie), etc.
There are a few different features within webquery, some that allow you to do olap and other offline stuff.
I took on the old version a gene cobb webquery class that common offered that was "online" (you logged into ibm and you were "trained", then you played with your copy), similar to the ones that they offer at common.
It has alot of power, it is fast and one day the executive staff was meeting on an issue to which I had a database of the information, and I had created several canned "reports" and graphs but they said, what if we exclude this or what if we only look at certain years, etc. and a few mouse clicks and a few keystrokes and voila, they had what they were after.
Honestly, it would behoove anyone thinking about it, to download it and take the 70 day trial of it, and if you are a common member consider taking one of their all day remote classes on it or see it in action at common.
It of course uses sqe, not cqe, so it is faster than old query/400.
And if you know what you are doing, you can create dashboards by taking elements from it and slapping them on a webpage as I seen done (but haven't done myself).
It has depending on the features you get, drill-ability, so that you can drill down to see what makes it up. Over at the ibm site, there is like an 18 minute video that is on webquery and some things you can do. That is version 1.1, (or it was last time I checked), but new version is even slicker.
under solutions there is a hyperlink for seeing some of the demo's.