Nobody answered. The problem is probably LiveView, which is new to DSLR's. Olympus have had it for a while, alond with an anti-dust system that really works, tiny body, Olympus looks great on paper. It's just that :

1. Nikon and Canon dominate the DSLR market. Olympus are struggling with Sony and Pentax/Samsung to be in the top 5
2. The Olympus sensor is smaller than the other manufacturers and has more noise.
3. There are fewer lenses available for Olympus than the others (no independent manufacturers)

If you want to satisfy your father then go for a Canon 450D - but get him to pay the difference with the 400D