Yeah. I've been repeating it a bit lately since the Ancelotti hype went through the roof, but so far in his career he is a cup manager in the mould of Benitez. He has time to improve his ability to handle leagues though as he isn't retiring anytime soon.
Well, it's true he only won one Scudetto, but it is very unfair to judge him on that and not take 'Calciopoli' into account. Before Calciopoli it was looking good and during/after he still made two finals. And him winning the league with PSG and Chelsea proves there's no reason to qualify him as merely a cup manager.
Look at his performances with AC Milan
2001-2002: In his first year he took over during the season from Fatih Terim.
2002-2003: First full season finish 3th and wins Champions League.
2003-2004: Second full season win the league.
2004-2005: Calciopoli with Juve. Champions League Final vs. Liverpool.
2005-2006: Calciopoli 30 point deduction for Milan
2006-2007: Calciopoli 8 point deduction in league. Wins Champions League.
2007-2008: Recovering from Calciopoli, money problems finishing 5th
2009-2009: Recovering finishing 3th.
So he was looking good until the Italian Mafia tendencies took over the league. Very hard to judge 5 of his full 7 years in charge because of that. Calciopoli had a huge impact and Berlusconi's power and money fading/strange times make it hard to judge his Serie-A performances.