The phrase "are often impressed by" is correct and usable in written English.
It can be used when expressing that people frequently have a positive reaction or admiration towards something or someone.
Example: "Many students are often impressed by the dedication and passion of their teachers."
Alternatives: "frequently admire" or "often find impressive".
Visitors to Washington are often impressed by the size of the president's entourage.
Selectors are often impressed by applicants who can show they are reflective and determined.
Policy makers in Washington are often impressed by this line, although less frequently than they used to be.
Judges are often impressed by serious market research: the results of customer surveys, for example, or of pilot sales programs.
Understandably, Mr. Jones's clients are often impressed by his mobile wizardry -- to such an extent that he once sold a million-dollar house to a customer in Philadelphia without leaving the front seat of his car.
I don't have any myself, but I am often impressed by the artistry of the tattoos I see at the gym and around town.
"I'm often impressed by this scholarship, but I'm also concerned that this new field seems to be so disconnected from the history of literature and scholarship that goes before it," Guillory said.
One of my favorite newsletters is "What We're Reading". It's a simple roundup of great stories from around the web, suggested by New York Times reporters and editors, and I'm often impressed by the range of my colleagues' interests.
I am often impressed by the way in which school children campaign against discrimination and prejudice.
I'm often impressed by people working to prevent outbreaks of nasty viruses with rapid vaccination development or others creating systems to radically improve the energy efficiency of large buildings.
European authors and chroniclers were often impressed by what they perceived as exemplary frugality, simplicity and moderation.
