Absolutely love it. I've used it for four days now, so I will update if I end up breaking out, but so far so good (and I often react very quickly to products). It has a light tint that is fairly undetectable on my skin (NC20), but it makes me look very glowy and polished. (I powder over it with Silk Naturals Blur powder, which I love). It's like my skin on the days when I wear makeup (just sheer foundation) except BETTER, because the SC PF doesn't settle into lines or create foundationy streaks on my nose where my glasses rest, and is not as shiny as fdtn. It also feels basically like nothing on compared to most makeup and sunscreens. I used to wear La Roche Posay Anthelios XL Fluid and it always caked around my nose where glasses rest and would be shiny, streaky white in places on my face, it never dried completely throughout the day and would settle into my lines. still i bore with it for the sake of the protection.
According to Skinceuticals, this has a PPD of 21, which is very high. It's also physical which means that it doesn't need to be reapplied like chemical sunscreen unless it is being wiped off (which does happen a little throughout the day, but I still feel more protected than when I wore chemical sunscreen for 10+ hours).
Anyways, I love it. It feels good on, looks GREAT on (polished as if I have light fdtn or tinted moisturizer on, glowy, but without caking, ever), is supposed to be very protective (and muaers have reported no pigment darkening or spots while wearing this in the sun). It's holy grail status. It does supposedly sting if your skin is sensitive (like if you're on a retinoid). I'm not currently using any actives and my skin has a very slight tingling sensation after applying, but no discomfort.
The main drawback is the price. It is very pricey--but it's completely worth it. I haven't found a sunscreen I like this much since Sofina.. and with a PPD of 21? I'm in, basically forever, unless my skin revolts or the protection ends up being shitty. I pile it on to make sure I have enough protection and it looks great.
[ETA: I did repurchase, but after a few months I realized all was not right with my skin. I was having overall very rough textured skin and many breakouts around my jaw and chin. It took me a long time to realize what was the matter, as I incorporated a few new items around the same time, and the breakouts came a few weeks after starting SCPF. After 3 months of loyal use and trying to blame every other product I've used, I finally quit SCPF and my skin is healing. Too bad, as this was HG material for me in terms of the tinted finish and all-day lasting power. ]
EDITED AGAIN: Later found out mineral oil cleansing was 100% the culprit for me. This may have been fine but I use other products now so I can't say whether it disagreed or not with my skin.. editing this back to 5 stars as it was once a great product for me.