Hello,

This is just my opinion, but i strongly believe (before we start another endless discussion on which is the better hybrid system) that we should all leave the technicalities regarding the hybrid systems for toyota and honda to figure out.
The bottom line is, These two cars CAN EASILY do roughly 44 - 48MPG when driven correctly (if anyone is not even satisfied with those figures is beyond me) , therefore, if you're asking about the advantages regarding which has better mileage, the answer is , there is no advantage of getting one over the other.

Depending on how you drive, it will affect both cars anyway, therefore, I suggest that you seek out advantages and disadvantages about the two different car's other aspects instead, such as drivability, cargo space, interior room, feel, looks, price etc.
If you're planning to go buy either one, I suggest you take your time and choose the one that meets your lifestyle needs and suit your budget.
and that can only be achieved by having YOU physically going out and test driving both.

regards,
gj