I keep having the lagg issue when typing in landscape mode. I don't know what the deal is with that. I run a task killer and reboot every couple of days. If I don't reboot, my available ram will drop below 200MB and when it does, that's when the lagg ensues. I absolutely love the phone otherwise. I couldn't be happier. I've had it a week, so it's almost time to root.
Known bug here's how to correct it for now:
Go to settings>language & input>uncheck Spelling Correction.
This doesn't remove autocorrect/spell check, it's just a bug that causes landscape typing to lag after 1-2 lines of text.