I would think that Reddit would have an advantage here in some ways. As an advertiser, instead of trying to pick interests of a general population, you can just pick specific subreddits.

If a store sells geeky/sci-fi clothing and gifts then I found it is way better to just target anyone that visits /r/startrek and some other relevant subreddits. No need to build profiles on users.

I found Facebook to be a lot harder to accurately target users as you are relying on Facebook's profile of a user. I got a lot more reach, but much less conversion.