I have noticed but it's off and on. Sometimes it loads fast and other times I click a link then check my email because I am impatient LOL. But overall the lag isn't as bad as you get in general on the web, nothing that made me feel like throwing the computer across the room as I navigated the site today.
I do know this - xenforo dropped the ball by not keeping the vbulletin reputation comments as a feature. The loss of the Reputation comments data when we switched to Xenforo really was the death knell for the site when it came to all the users that left. I know I missed it so much and I got way less interested in the site when that feature was gone and I run the site.