From the most recent several weeks of slush encountered, here are some random facts.
Longest read before a no: 70 pages
Shortest read: 3 paragraphs.
Most common reason for rejection: lack of interest in the main character.
Second most common reason for rejection: Unsupportable plotting quirks.
And yes, I'm still bemused by people who send me query letters via the contact form. Especially since this is directly below the contract form:
Any one who attempts to submit or query through this form will have their email address banned across the whole domain.
And of course it is nearly always for something I don't represent in the first place.