I'm sorry to be late in the game on this thread but I have only recently signed up to tpf so this is my first post. This forum has been a fun place to lurk.
I know my feedback may be too late because you may have bought something already but just in case here is my experience.
When I started out buying Hermes I didn't have any kids. I now have kids and since then have been in search of the perfect bag to fulfill those needs. While I don't use any particular bag as a full time diaper bag I wanted to find something that could hold a lot so I didn't have to carry a diaper bag and handbag at the same time. I then proceeded to buy a garden party, DS, evelyn and jypsiere.
Of those I use the jypsiere the least. I have the original version and the buckle sometimes becomes undone and the belt straps were too fussy for me. It also doesn't have enough space for my needs when carry things for the kids.
The evelyn is great for being hands free but really doesn't hold a lot so you have to keep it simple and light on the kids stuff. This is the good bag if you don't need to carry much baby stuff.
I love my garden party bags a lot. I can really hold a lot and if you don't have tons you can even snap the top and sides to make it a bit more secure. The straps are long enough to carry on my shoulder if needed but may be a bit tight with a winter coat. It is also lined in fabric so if anything spills, it is a bit harder to clean. This is assuming you have a leather gp. The toile gp is not lined and so it is more sturdy and lighter. I once spilled hot chocolate on my toile gp and it cleaned up very nicely with some wipes. Thank goodness!!
I have had my DS for a few years now and at first didn't use it a lot. I also wondered if I was spending too much on a plain leather tote. But, I have recently used it more have come to appreciate it a lot more. It is holds a lot, sturdy, strong, leather cleans up easily and the straps are long enough to have a winter coat on too for shoulder carrying. The down side is that it can get heavy since it is a lot of leather and when filled to the brim which I have done.
Good luck on your search for the perfect fashionable mommy bag! Hope this helped a little.