I don't own any, but I have a friend who does. She likes them for the very reason you mentioned -- they are light weight. I'd like to learn more about them. They are so feminine and dainty, yet durable!
I used to carry them in college quite a bit. I didn't like how they got dirty so fast, they really seemed to attract the dirt - and I'm really careful about my bags. I do still have a huge duffel bag that I use for weekend getaways etc. and I love that bag. My Hubby got it for my with my name embroidered on the side.
I carry them all year round. I have a Mediterranean blue tote that I am using now. And an older pink/peach print that will come out for the warmer months. I do love that they are lightweight, no back or shoulder problems from these bags!
I love them in the summer. I have a few "Miller" bags for the beach and the pool. They have 6 inside pockets and zipper closure. The back sack style is cute also. So many members here hate on this brand, but to each their own.
I use the totes a lot when traveling. My sister has a laptop bag..at least I think its a laptop bag,..she carries it with her EVERYWHERE! I guess it is so super lightweight that it makes it easier for her to carry her laptop and books without weighing her down as much. It is amazing it can handle the weight though.
I personally don't carry VB, though I received one as a gift for a wedding I was in.
They are way too floral/hobby lobby/suburbs vibe to them that just doesn't go with my wardrobe. Though for whatever reason, I love my 1154 Lill... I think because when you design your own fabric bags, you can choose just how bright and floral you want to go and I like being able to choose more modern and abstract prints. I also love the Orla Kiely bags!