The Dutchman sealed his ?24million move from Arsenal last week and is in line to make his debut in Monday Night Football when United travel to Goodison Park.
Giggs feels the Dutchman has lifted the club following his arrival.
"Robin looks good," said Giggs.
"You can see just from one training session the qualities he has, which we know all about anyway because of all the times we've played against him.
"He brought that lift to training that a top player brings and that all bodes well for us.
"The players are just like the fans in terms of talking about who we might sign and wondering which players might come in.
"It's always very exciting for us when we sign new players, because you know that whoever comes in will have a lot of quality and will improve the team.
"Van Persie's movement is so good and he's got a real presence. He's big and strong with a great left foot and he scores all types of goals - poacher type goals, goals from long distance, free-kicks, penalties.
"He's just an all-round top player. And he's improved so much over the last few years as we've seen by his performances and his goals.
"He's a good guy and he's fitted in really quickly with the lads on and off the pitch. It's a good dressing room to come into.
"There's a good team spirit and the lads are always great at making a new player feel welcome."
And Giggs feels that van Persie is capable of playing with any of the forwards at the club already.
"No matter what partnership the manager goes with up front, it looks mouth-watering," said Giggs.
"It's not just about the type of goals we know all the strikers can score, but the movement they have and their all-round play.
"Whoever the manager puts out there will do well, I'm sure. It's the manager's job to juggle all the players and pick the right systems for the right games.
"We all know that if you go on cup runs and Champions League runs, you need strength in depth in the squad because you're going to get injuries and suspensions and dips in form.
"So you need a big squad to compete at the top. They [Welbeck and Hernandez] are young lads and good lads who want to learn.
"They've already learnt a lot from Wayne and you've seen the improvement from both players. There's no doubt Danny and Chicha [Hernandez] will learn plenty from Robin."