As a side note though, I'm not sure about the saftey of using lamb bags at school.I have a westfield and LOVE it. I love montego's too, I just down't own one yet. Anyway - for school purposes I think the westfield would be better. I've used mine for school a couple times and it was very convenient. The montego might not hold folders well because it it's rounded shape, and the fact that it's hand carry means it could get very heavy.
As a side note though, I'm not sure about the saftey of using lamb bags at school. I only brought my westfield a couple times and then got worried that something would happen to it. That just me though, I'm not very brave lol.