I think I might have figured out why the new Evernote is so slow and laggy for me. Laggy to the point of being unusable; it's as if every character I type has to go to the server for validation and back before it appears on my screen. I can sometimes type an entire sentence and be on the 10th word before anything appears on the screen.
I think it's because each of my notes is so big.
Here's how I use EN: I manage about 25 different documentation projects, and each project has a note in EN. Whenever I work on a project, I enter the to-do list, task descriptions, and other notes, in a dated entry. So basically each note is like a blog for the project, where I have a running history of the work done. Notes run anywhere from 10,000 to 20,000 words at this point, because some of those projects have been running for six years or more.
So I think that's the problem; the notes are too big. I'm not going to change my process, so obviously I have to find another notes application.
I'm just noting this here for the sake of other people who have severe lag problems; it might be because your notes are too large.