I find benzoyl peroxide is best for white heads because it dries them out. For cystic acne though, I use salicylic acid because it exfoliates and gets down into the acne to help clear it better. So depending on what type of acne you have, you can use either :)

If your skin isn't to sensitive, you could try using a salicylic acid cleanser in the morning and a benzoyl peroxide cleanser at night. I used to do that because I used to have both cystic acne and whiteheads so each issue was addressed.

Ive had a lot of luck with the Clean and Clear Continous Control cleanser. Its 10% BP though so if thats to strong you can try the C&C advantage 3 in 1 exfoliating cleanser which is 5% BP.

If you have to use one of those two, definitely Benzoyl Peroxide. Salicyclic Acid is the same thing a beta hydroxy acid.

I have never had any luck with salicylic acid when dealing with my mild acne. Benzoyl peroxide is the only thing that has ever cleared it up. I use Proactiv and have been for close to 7 years now and swear by it.

I use salicylic acid.  I find it more suitable and gentle on my skin.  Aside from clearing my face, it acts as an exfoliant as well.  The copper peel from omorovicza also works well on my skin. 

I find that it depends on your skin for which works best.  Sometimes a combination of Benzoyl Peroxide and Salicylic Acid even works well for some.

I use a moisturizer with salicylic acid, and then use a 2.5% spot cream with benzoyl peroxide. It works best for my skin, but everyone is different. I normally have very mild acne (white heads) and this regimen keeps it under control for me. It's all about finding something that works for your type of skin.

Acne treatment is very much about trial and error, unfortunately. Different acne treatments work for different people... I would say that SA is less harsh but not necessarily less effective. The concentration of the active ingredient is another thing to take into consideration, or you could even combine them. Neither worked for me though--I've tried both in varying concentrations, and prescription treatments. The only thing that worked for me was Accutane, but every body is different!