Hi Elpgal -- I've tried several PC products and for me the must-have is the 1% BHA lotion (very dry, very sensitive skin). I also like to have the body AHA (10%?) around though I go through phases of using it.
PC has cheap samples, fast shipping, good CS to a nice line to explore.
I used the Vitamin C and the low-dose retinol (.5%?) nightly for several months and they were fine but I felt like I stopped seeing the initial benefit (Vit C brightening especially) so I stopped. Would get back into the Vit C -- great price for the product.
I really hate trying new skin/makeup products due to my extreme sensitivity, so once I find products I like I stick to them.
My go-to line is the derm-developed and Epionce, available online and some retail. Very good price point for derm developed and lots of great info on the brand's site (look for the stuff aimed at pros.]
[I use Lovely Skin to order as they consistently have 20% specials, also pretty extensive reviews.] Cleanser, moisturizer, eye cream, SPF 50 for rain or shine. If I had to choose one product I'd pick the SPF!