Frakes was honoured with a Life Career Award at the 39th Saturn Awards in 2013.
From the Press Release:
The Academy of Science Fiction, Fantasy & Horror Films is happy to announce that actor and director JONATHAN FRAKES, whose impressive body of work includes playing Commander William T. Riker in Star Trek: The Next Generation and its big-screen movies as well as directing such series as Castle, NCIS: Los Angeles, Leverage, Roswell, and V, will receive this year’s Life Career Award.
He joins this year’s previously announced special-award recipients Richard Matheson, William Friedkin, and Vince Gilligan and will receive his award in person during the award ceremonies.
He was given the award at least partly for his efforts during TNG's television run.
About the Saturn Awards:
The Saturn Awards is the official award presentation voted by the members of the The Academy of Science Fiction, Fantasy, and Horror Films.
The Saturn Awards is an acknowledgement of fine work. Some of it is ground-breaking, some of it is vastly entertaining, but the bottom line should be that the recognition is well earned.
Frakes is the only TNG actor to have received a Saturn Award, let alone a Life Career Award. (Patrick Stewart was nominated three times for a Saturn Award, but never won one.)
This particular recognition puts Frakes amongst the likes of individuals such as Ray Bradbury and Gene Roddenberry, and actors Rock Hudson, Ann Robinson, Vincent Price, Lance Henriksen, and Malcolm McDowell — each received a Saturn Award.
(Source)
Regarding praise for specific instances of Frakes' portrayal of Riker on television, the official Star Trek site very recently posted a retrospective on the Riker-centric episode "Frame of Mind":
The article is quick to point out:
The season-six hour remains a fan favorite, in large part thanks to the powerful performance by Jonathan Frakes, who plays Riker as a man losing his mind in the complex, layered, even trippy dramatic episode.