The United trio was better individually, but I think the Liverpool front three at their best was actually better as a unit. The rest of the team wasn't as good then, but the attack peaked in 17/18, especially during that CL run.
They had 44 g/a between them in CL that campaign.
I half agree on Vidic. He definitely had his limitations, but he was an absolute monster against the long balls and crosses style of football most teams played in PL during his peak.
He might have struggled a bit for a team like Barca or Madrid in La Liga, but he was the best defender in PL for a few seasons and probably the most important player overall in the league for 2010/11 season.