Two players who are/were often willing to sacrifice their individual productivity if it means their teams could benefit from it.
Benzema didn't get the plaudits he deserved from the neutral during the years when Ronaldo had the spotlight at Real Madrid. He is definitely receiving the plaudits since Ronaldo's departure though. Hence he is no longer underrated. His ability to hold the ball up and bring others into play is one of the best in the world. Top 3 in the world along with Lewandowski and Kane IMO. Benzema has excellent movement that enables him to draw defenders out of position and creates space for his team mates to make attacking runs. Rooney was technically skilled. However, Benzema was superior in terms of close ball control and had a neater touch. He is more refined technically and classier on the eye. He had better balance, was more elegant and is also a greater threat in the air than Rooney was.
Rooney was blessed with stronger physical attributes than Benzema. Benzema is deceptively quick and agile for his size, however Rooney had a frightening blend of great acceleration, incredible strength and perhaps most notably, a fierce level of determination that enables him to simply power his way past defenders with relative ease. When he was a teenager, Rooney was already constantly outmuscling veteran PL defenders. He played with a level of intensity and energy that was infectious to his team mates, but intimidating to his opponents. He had seemingly limitless stamina and rather than staying upfront would bomb all over the pitch to be involved in the defensive side of things and build-up play. Rooney excelled in pressing opponents to win the ball back and was a surprisingly good tackler. He was the better dribbler and also had a brilliant passing range. There was an edge of the seat excitement from Rooney that I didn't get while watching Benzema.
Benzema gets into more goalscoring positions due to his superior movement, however Rooney is the more accurate finisher of the two. He didn't miss as many easy chances as Benzema. Both are/were great strikers of the ball who can score from different angles and in a variety of ways; volleys, long range screamers, overhead kicks. Perhaps Rooney was better in chips/lobs, free-kicks and halfway-line shots. Both were creatively gifted and adept at making the killer pass/final ball. I know Benzema has better stats than Rooney. However, I don't think statistics tell the full story. For e.g. the likes of Scholes and Iniesta had less assists than Beckham, Lampard and Gerrard. Some of Rooney's assists were absolutely sublime and put it on a plate passes.
Rooney was extremely versatile and dovetail well with all the strike partners throughout his career, regardless what style of play they had. RVN, Owen, Saha, Solskjaer, Ronaldo, Tevez, Berbatov, Hernandez, RVP. There isn't a striker that he isn't compatible or doesn't gel with. In an ideal world, you would have both Rooney and Benzema playing with each other on the same team.