For starters, the Laura Geller Filter Finish Setting Powder is a bit cheaper at $32, while the YSL Gypsy Opale Face Palette is pricier at $47. The price point is certainly shown in the packaging--the Laura Geller comes in a slightly cheap looking, clear compact. The YSL one comes in the classic YSL gold compact, which includes a mirror, and has a beautiful rainbow design on the front. It's also limited edition, so is going to be harder to find and won't be around much longer. I personally prefer the YSL packaging, as it's more luxe, and I also like the design better. To be honest, both perform very well--I use them either on top of liquid foundation or as I set my whole face, and I really do see a glow. I wouldn't normally use this type of powder on its own, but as an addition to foundation. The Laura Geller one is a bit of a lighter, more powdery texture, while the YSL powder feels a bit more high coverage. Another benefit of the YSL one is that the colored powders are individually separated, so if you just wanted to use the purple one, you could (although you would need a very small brush).
If you're just looking for a good, all-around color correcting face powder, I would suggest the cheaper Laura Geller option. But if you're a makeup aficionado like me who loves limited-edition product, I think the YSL one performs just a little bit better and is worth the splurge. I'm not sure you need both, but they're both lovely products and it just depends on preference. If you know of any more affordable color correcting powders, please share below!