I love everything about this! I have extremely dry skin, to thr point of cracking and flaking, and I was using moisturizers that didn't give me as much hydration as I needed. This stuff soaks into your skin sooo well. My skin even continued to look good after applying makeup (which is when the dry patches usually love to shine). You only need maybe 2-3 pea sized amounts for your whole face depending on how much hydration you need. The effects continued on into the next day. I did have to reapply of course, but my skin looked less damaged and cracked when I woke up. Also it has a nice scent that's not too overwhelming.
The main negative for some people would be the price. It's more than $100 so that's not in everyone's budget. La Mer gives away generous sample sizes on FB...so I'd try liking their page and posts and see if any ads pop up. Grab all the samples you can from them!
Also if you're using this in your morning routine, you'll probably have to wait a little bit longer for it to dry (or be absorbed) before applying makeup. Some people might just prefer to use this at night for that reason.