This word cloud shows the 25 mis-transcriptions I found when I compared Ancestry's transcription with Find My Past's for the 1841 England and Wales Census. All the corrections were submitted but it has highlighted a need not to rely on one company and, as one of my G+ followers pointed out 'wildcard searches are a must'.
I must admit though, I'd have never thought to look for Weares (Stears) or Keer(s).