For use cases like that it is incredibly similar if you give the --verbose flag:

    $ units --verbose
    [header]
    You have: furlongs per fortnight
    You want: m/s
            furlongs per fortnight = 0.00016630952 m/s
            furlongs per fortnight = (1 / 6012.8848) m/s
    You have: 17 yards + 2 feet + 5 inches
    You want: meter
            17 yards + 2 feet + 5 inches = 16.2814 meter
            17 yards + 2 feet + 5 inches = (1 / 0.06141978) meter

Personally, I find qalc via qalculate-gtk more useful for exploratory sessions but I still use units an awful lot.