Pretty Good

Seems to work as advertised (havent tried the watch app). One thing to note is that The Converted doesnt convert between units with reciprocal relationships (mpg and l/100 km, for example). Obviously much harder for the developer to do, even if the conversion is limited to a specific range (5-200 mpg, say). However, a scale is probably most useful for the conversions that are tough to visualize.

Aspiring Tuna about The Converted, v2.5.1