Seems that no one has posted this fix for landscape lag yet.
Settings>Language & Input>Uncheck Spelling Correction under top Language tab (ONLY under here, leave it on in the Android keyboard settings)>Profit.
You'll still have all the great spelling corrections, but it cuts the keyboard lag in landscape in half if not more.
Edit: Site sucks to read like this, killing my head.
Edit 2: This phone is amazing, a week later and I still can't believe it. Those having 3G/Voice/Wifi issues, swap the phone out, LTE readings are finicky and I'm 99.9% sure that's ICS software not playing well with the radio just yet, but not connecting on the other 3 (short of a VZW outage) is likely HW.