Former Liverpool striker Berger said: "If I was in Gareth's position I would go there tomorrow. It is the opportunity of a lifetime. Liverpool don't come after you every year.
"He is the heart of our team and it would be a massive challenge for him. He would be in the Champions League and challenging to win trophies every year.
"I'm not surprised they want to sign him. He has had a fantastic season and was our main player from the beginning to the end. He has played well for the national team as well. But I think the gap - not just between Villa and the top four but the rest of the League - is big. To break into the top four you would really have to spend a lot of money.
"Everton have tried for the past few years but they only did it once. It is going to be tough for Villa to do that. It will take time and to reach the Champions League you would need to keep players like Gareth."