I had some lag before if I connected to some friends but other friends were fine and quickplay was flawless with regards to lag.
Now after 1.0.3 I get lag all the time, it is somewhere between 0.5-2 seconds of input lag. Sometimes skaven and norscas teleport around (though only when it is really bad).
Nothing has changed with my own internet afaik.
When are the dedicated servers coming?