I have the same issue. I keep hold down the "a" key and it will print 5 then stop for a sec, print another 30+- then stop a sec, print another 30+- or so and stop for a sec. Same thing with erasing. There is a lag while typing. I even disabled on demand sync and sync in the background.
I have this issue at home computer (Windows 10) and at work computer (Windows 8) for the last few months already.
And yes the web version is definitely better. Hold down the "a" key and there is no lag printing it.