I struggled with this decision myself just a few months ago. I ended up choosing the Venetia as my 1st, and I loved it so much that I bought the Blake shortly after! Both of mine are non-quilted, which I personally prefer to the quilted.
I like the Venetia best. I like the style of it best (so sophisticated), and I like that it is wider, but not as deep as the Blake, so it does not stand away from my body as much as the Blake. I also like that the Venetia just has one large compartment, rather than the 3 that the Blake has. I know a lot of people prefer the divided compartments of the Blake, though. I thought the middle strap on the Venetia would bother me, but it doesn't. I just leave it undone most of the time. The Blake is a better shoulder bag. The Venetia is primarily handheld, though it does fit on my shoulder since I'm small, but it's tight.
Since those are the only 2 I own, those are the only ones I can give you a lot of detail about. I also like the Elise, but I did find that they are harder to come by. And I prefer double straps and the "satchel" style, so I didn't really look at the Multipocket, though it is a great bag, too.
MJ bags are heavy - the heaviest I own! But that's not bothered me too much.
Let us know what you decide!