Sry for the later reply, but I have both bags so I I thought I'd give you my input, if you haven't already decided.
I have the medium envelope in the pale pink color. Got it a little over a year ago. Gorgeous style, BUT the quality is atrocious!
The leather on the flap has completely rubbed off the tip, on the corners & top of the back pocket... basically everywhere you can see the gray coming thru underneath. This started happening WITHIN 2 WEEKS of me having the bag! Took it to Saint Laurent boutique where it was purchased. The rude SA said it was "normal wear& tear" and that it was my fault. Offered no remedy. (I didn't want a new bag, just to have it sent out/repaired by them sine it was well w/n the One Year Warranty. She said I would have to pay $100's to have it "repaired" by their cobbler, and if he damaged it, I was SOL. I can send it to my own cobbler, whom I trust and is prob cheaper. So, no thanks). I also have several friends (at least 4) that had this same prob. They luckily all bought theirs at
Nordstrom, so they were able to return for a diff. style. Also, keep in mind that you can't fit much in this bag since it's super stiff & structured. I still own it, but I don't grab for it often. I've carried her no more than 10x since I was gifted the bag in early April 2018.
I recently got the LouLou in the medium size, black w/ ghw. I have been using her everyday for the past 2 weeks! So spacious, but also look luxurious. The leather is so soft & I hope there won't be an issue with the rubbing. So far, so good.... so keep your fingers crossed! Can also easily be transitioned from day into night also.
1 Vote LouLou... just b/c the quality of the envelope is very poor