The one feature/program I really admired in OSX was Alfred: a smart application/file launcher.
Alfred returned incredibly relevant results after only typing a single character - for example, 'C' always matched Chrome as it was the most used application on my system beginning with 'C'.
Unfortunately Kubuntu's equivalent, KRunner, requires at least 3 characters to match, does not perform fuzzy logic (so is not forgiving with typos), and I get the impression it doesn't order by most-used. It also seems to favor emails, open windows and files over applications... I may not be entirely accurate on the latter two, but suffice to say the top suggestion in KRunner is infrequently what I expect.
Does anyone know of any alternatives? Overall I am finding Kubuntu far more productive than OSX... I just wish it had Alfred :P