Collins chose Stoke ahead of Wolves when he left Sunderland in the summer, much to the disappointment of McCarthy.
"Mick is the sort of manager who will say his office is open if you want to have a chat. He can be nice but, when he needs to be, he can tear into the lads and give them what for. Is he scarier than Roy? I would say so, yeah - and he's a bigger bloke as well!
"Mick was never too much into chucking stuff about - only maybe a cup of tea - but it was his presence.
"I remember on a few occasions where he said 'If anyone wants to sort it we'll go in the gym with gloves on!' There weren't too many takers. Mick signed me for £150,000 from Chester. He gave me my chance at Sunderland and I owe him for that one.
"We won the league that season but, unfortunately, Mick did not have much money to spend and we had a bad season. Mick lost his job and we went down with 15 points. But he's a top bloke and a top manager to work for."