All of a track's information can by synced using Rekord Buddy. This of course includes things like Title, Artist, etc… but also the track's beat grid and any cue points or hot cues.
You can also choose to sync only certain fields in order, for example, to update only part of a track's fields between the two programs.
And since many different musical notations are available for a track's key, Rekord Buddy will automatically translate them to the standard notation (with or without sharps), open key or any other notation you wish to use.
By far the easiest way to unify the information from two different collections if you're already using both Traktor and Rekorbox.