They both follow the same Trainee Driver recruitment process set by the OPC, so technically, there isn't much difference in terms of difficulty getting in. Some companies will use Enhanced Scoring during the assessments, so the pass marks required may vary slightly from company to company, but both passenger and freight companies may or may not used Enhanced scoring.
Realistically, it's just a case of weighing up whether you'd prefer to do passenger or freight work, and of course, consider the all important 'how long it will take you to get to work' and then apply away.
