Brown made his debut during the Black Cats' 1-1 draw away at Liverpool on Saturday afternoon and his performance received praise from a number of pundits.
Like 31-year-old Brown, Bardsley was deemed surplus to requirement at Old Trafford in 2008 and he has expressed his happiness the former England international has joined him at the Stadium of Light.
"Sir Alex makes some decisions and this one has come in favour for us because if Wes plays like that [against Liverpool], he's up there as one of the best centre-halves in the country," Bardsley told the Sunderland Echo.
"I have played with him before and I know what he can do. When he plays like he did on Saturday he's top class.
"He's got unbelievable composure and in the air he wins everything. Overall, he's a fantastic player and a great lad as well."
Brown joined Steve Bruce's men for a reported £1m fee from United.