You could possibly be up and running in a little over an hour but I would spend time reading the comprehensive manual first or you'll miss a lot of useful stuff.
Good enquiry form, booking form, a number of ways to display availability, powerful backend features including financial reporting - the list is huge.
I have not yet had any need for support but, reading the comments below, I would not be worried.
Although it is not yet on a production site, all tests so far have sailed through without errors.
The extension is only being used for one rental on our site but it would be a snip to add others.
Not often (if ever) I write a review but this is just so well thought out - good work!