I like the look of both and own both, but on a daily basis I most often wear slouchy bags. I just find them more comfortable and I like the ease of the smooshy leather bag.
Normally I prefer slouchy. But I need a couple of structured ones for dressier events. Or when I know I need to put it down on a somewhat dubious surface... I'd feel far more relaxed doing that to a structured bag with feet.
I love the feeling of that soft puddle of leather (hello Prada leathers!), but the collection overall still consists of structured bags such as flaps and satchels.