I've waited 4 months before writing on here as I wanted to give the product a fair shot. While it might not be for everyone, it HAS worked for me so if this review can be of use to anyone then I'll be happy.
For the first week I only used it on alternate days, finally building up to twice a day every day. I don't know if it was the skinoren or the UV lamp I started using (Beauty Skin by Dr Kern - another fantastic product), but within the first few weeks I definitely had a purge. Not terrible, at most 6-7 papules, and certainly not as big as my previous pimples.
After this my skin has really improved: I went from a lot of whiteheads (clogged pores) and papules to almost no whiteheads nor any sort of papules. While the whiteheads were 'coming out' there was some redness, but this was temporary and the marks have nearly all but faded.
I still get the occasional hormonal pimple but these are much much smaller than 4 months ago and go within a few days (unlike a few weeks). I would definitely recommend this product to people who are sensitive to Retin-A and BP, as I was. Please do remember that I am using this in conjunction with the UV lamp, which is excellent.
Altogether I am very happy and I hope you can be too. Thanks for reading and good luck!