If you were running SQL version of NTA 4.0.2 (typically because of having 32bit AP in you environment) and trying to upgrade you might see message similar to "Error: Empty hostname or IP address.", to resolve it you would have to uninstall NTA 4.0.2 and then install NTA 4.1.0. This procedure doesn't erase your data.
No other known issues I am aware of.
sorry for late answer but Xmas and all that mass .... :-)
Anyway I found not any issues during upgrade.