The biggest issue is the predict when typing. Anytime I type the word "is" the phone inserts "OEM", "of" gets "OCD inserted, etc. I have deleted all of my saved words from the user dictionary but it continues to happen.
Second, sometimes when typing the keyboard will become unresponsive. For example, if I try to tap the "k" with my right thumb sometimes the keyboard will not respond and I have to use my left thumb to get the "k" typed.