Bike bags - Things to look for

berman

I've be trawling the interent for some hours and whilst each review offers a different spin on things I just wanted to get some honest opinions on bike bags! What would you recommend?

I'lve looked at most the cases below, but nothing jumps out apart from the semi structure case from Polaris in green.
http://www.bikeradar.com/gear/article/best-bike-boxes-and-bike-bags-33421/

Thanks.