Overall, I rate the riverwalk in Little Rock as one of its best attractions, primarily because it offers connections to many downtown attractions, and is an attraction within itself.
First, the riverwalk runs (or will run) from the Clinton Library on the east, down to about the Old State House Museum on the west. The walk is actually part of a 28-mile walking and biking trail on both sides of the Arkansas River.
The walkway runs behind The Museum of Discovery (children's museum), a free Arkansas nature center on the river, the Little Rock Farmer's Market and restaurant area, the Junction Bridge (allowing foot and bike access across the Arkansas River, and to the submarine U.S.S. Razorback on the opposite side), the Peabody Hotel and the Old Statehouse Museum.
The riverwalk itself contains some of the rocks on historic display that at one time were used as the basis to survey the city, hence, the name "Little Rock." There's also a playground and children's fountain for hot days, historic markers telling information about the city, the river, and the Civil War battle of Little Rock, fought in part along the edge of the walkway. There's also an outdoor theater for programs.
This is one riverwalk that seems to have been built right, and serves its purpose well. Parking is available at various spots, but parking directly by the riverwalk is available only by the Farmer's Market, or if you stay at the Peabody Hotel.
One minor note, as you go west, some of the downtown area access (especially around the Old State House Museum) requires a bit of a hike to access from the riverwalk. You will also probably see homeless people on benches, too. But the Peabody Hotel, for example, has easy access to the walkway. Other attractions, like the Arkansas Territorial Museum, are a bit inland from the walkway, but not out of reach.
The walkway makes for a pleasant way to get around downtown Little Rock.