DEE-DUCK,
I can't make any comparison with the Japanese medicals, but, with one exception, I would put it on a par with the Australian medical.
The exception is an overwhelming obsession with Cholestorol levels, either you're in 'the Green Band', or you're a fail. Fortunately, the airlines here understand this fact, and will give you the opportunity to get it down to acceptable levels before a retry.
Do yourself a favour, check it out privately now, get it down if necessary, and then approach the medical. It will save a lot of stuffing around.
The good thing is that once having passed it, they never bother to check again, renewals are awfully awfully routine.