AJAX On or Off?

Is there a consensus on whether AJAX should be turned on or off? (We are using 2.0.15)

We already determined using AJAX for pagination on the customer side was bad. If you had a list of 20 products, and were on page 2 or 3, if you go into a product that hit back to go back to the list, you briefly see page 1 first then it changes to the page you are on. Very weird - never seen another e-commerce site do that. Turning off Ajax pagination seems to alleviate that.