Barry admits his "one huge regret" about his 12 years at Villa was failing to land any silverware with a 2000 FA Cup final appearance the nearest he came to trophy glory.
But the England midfielder believes he can achieve those goals at Eastlands even though he has sacrificed his ambition to play Champions League football for at least one more season.
Barry said: "My one huge regret is that during my time at Aston Villa we have not brought the supporters the success they deserve.
"I obviously have to take my share of responsibility that we have not been good enough to win trophies.
"A lot of people will question my decision to join Manchester City.
"But they were the club prepared to meet the valuation which, for a 28-year-old with a year left on his contract, I think shows how much they wanted me."
Barry admits the fear of going stale and losing the edge to his game prompted him to move despite being optimistic about the future for Villa.
He said: "I feel the club is in the best position it has been in during my time at Villa.
"I think we have a group of very good young players, a fantastic chairman who is here for the good of the club, and one of the best managers in the game.
"But, after changing my mind lots of times, I came to the decision that the time was right for me and for the club to part company.
"I need a new challenge, I have a massive fear of going stale and falling into a comfort zone."