the old server did not want a username either just like this one as you are allowed to send an email via it as long as you are on an ntl ip range otherwise it will not allow you to send anything, the previous smtp server ignored the fact that there was an empty username, whereas this one does not and you need to untick it :s
as for the server upgrades i know there is a lot of testing being carried out for a couple of new features to be released soon which will please some of you
this could be causing it to run slower than normal