You all have made some really points. I think I'll buy the DE first. I think....I know I'm going to end up with both eventually! So much for being content! I'm hopeless!
I think it depends on your current collection. If it's smaller, I would go for the pochette, since it's more multifunctional. If you already have a few pieces, the Milla to spice things up!!
I have a de pochette and mono milla. I use the pochette for quick errands to fit essentials, the milla doesn't fit all essentials so I take that to fancy dinners with my husband and he carries the keys bc it won't fit in milla. The milla looks so elegant though I prefer to look at her over the pochette nm.