I use Skinceuticals and I love it. I guess it all depends on your skin concerns. I have sensitive, blemish-prone skin but since using Skinceuticals, no one believes that I actually have skin prone to acne. It makes my skin really healthy and glowy.
If you have normal skin; it may be not be worth spending alot of money on Skinceuticals but if you have some problems, its definitely a good brand for correcting various issues. Just like Schmodi mentioned, I incorporate other brands as well such as a cleanser from Chanel and a Burts Bee's toner but my stronger cleanser, night cream, moisturizers, and serums are all Skinceauticals.