I reckon that that is harder on guitar, and not just because of unfamiliarity with counting out different beat patterns. 3/4 can be done bar after bar with the same pick pattern, but would 5/4 become a two bar pattern maybe? It certainly takes you out of beginners territory. In a similar vein, why is a forward roll on five string banjo much easier than a backward roll? There is no obvious reason why it should be.