That's a difficult choice, especially since I've only had my GST since this past January and have only recently begun carrying it. I purchased my Cerf Tote in January, 2014, and have carried it quite a bit. Initially I thought it was a tad boxy, but with use it has softened up just a bit and in the best possible way! It's so easy to carry and not at all heavy. I'm 5'3 and 105# for reference. It is understated and so chic and classy. It's elegant in its simplicity and can easily be dressed up or worn casually on weekends or with denim. I always feel so put together when carrying this bag. It's perfect for travel as well because it's roomy and goes with everything. I'm very glad I have it in my collection. When I got this bag I was choosing between this and the GST in black / gold hardware. I wanted something that didn't " scream" Chanel and was more " clean" looking. My style is classic with a twist. I love adding personal touches with jewelry and amazing shoes. I wanted the bag to enhance, not compete.
When the rumors started swirling about GST being discontinued, I decided to add one to my collection and chose the beige/ gold for variety. I've only been using this bag for a little while and I do love it, but it's not as easy to carry as my Cerf Tote . I worry about it losing its shape and creasing over time. I definitely don't think it has " too much" going on, as I once did. The hardware is like jewelry on this bag. Both are tote style bags, which I love. The GST has compartments which provide interior organization. The Cerf is an open interior with a snap in/ out pouch. Both work well for my needs.
If asked today which I'd keep if I could only keep one, I'd choose my Cerf Tote. Sorry for the lengthy post, but hope it helps a little.