Yup, same here. Non-instanced content is largely OK (though sometimes teleports take an oddly long time). Is entirely related to time of day. We've played successfully in dungeons until prime time (>6pm EST) and then suddenly instances become untenable. In the most egregious example, we were in Stone Vigil HM with a FC party, and all four of us experienced >5s lag at the same time. Different machines, different ISPs, different physical locations, so there's no commonality unless you start counting regional (tier 1) network providers.

Either way SE's "reinstall your computer" is complete bollocks, as it's quite apparent its not localized to an individual machine or environment.

Here's to hoping the patch last night fixes it.