O'Neil totally overrated manager cocked up with Villa brought players in that cost a fortune and didnt play them. will never win a trophy yes he's a good motivator and man manager but expect crap football and still no trophies.
im not a villa fan but a fan of a L2 team but every job that comes up everyone wants O'Neil but to me Hughes would be a better bet for Sunderland.
Overrated? Have you taken leave of your senses? He has been a success at every club he has managed. (Barring Norwich, but there were reasons)
Wycombe Wanderers: Takes them from non-league to what is now League One in consecutive seasons and nearly takes them straight up to the Championship as well. Wins FA Trophy twice.
Leicester City: Consistently in the top 10 in the Premier League from 1997-2000 as well as winning the League Cup twice (1997, 2000) and being runners up (1999). Yes, that is three appearances in the final in 4 years, at Leicester.
Celtic: Wins three league titles, three scottish cups and a league cup, including the first treble for over 30 years. Some will argue about the competetive nature of the Scottish league but he also takes them to a Uefa cup final, no mean feat for a Scottish club.
Aston Villa: His time at Villa was not even a failure, taking a club that were constantly in the bottom half of the table and gradually progressing year on year culminating in constant European qualification of some sort. He also guided them to a League Cup final as well.
So yes, completely overrated.

I'd say that it was quite a mouth watering prospect for Sunderland fans, he will certainly bring stability and in all fairness, they have a pretty good squad as well.