What do you like best?
The query system. One of the most versatile among similar services. The Shareability / Influence sort options. Reasonable pricing, as compared to tools like buzzsumo.
What do you dislike?
Lack of integration - can't do much with the curated content except for RSS (which by nature, is far from ideal) and Hootsuite? (well, let's just say Hootsuite is not built for content curators, which is upcontent's main audience I would think)
Views - I personally prefer list view without images when Hearting. A magazine view for reading.
RSS - there is no way to get an RSS for Favourited items. Wondering what's the point of favoriting when there are no way to export them for distribution.
Recommendations to others considering the product
Try it! Do use the live chat if you need help like setting up of queries. One of the most awesome support around. The unique features you can't readily find elsewhere for the same costs are the Influence and Shareability sorting features.
Integration with your social posting scheduler might not be there unless you are a hootsuite user. Otherwise, your best bet is to make use of the RSS output (which is a nice feature by the way) and find ways (probably IFTTT or Zapier) to feed the RSS items into Buffer and whatever service you're using.
What business problems are you solving with the product? What benefits have you realized?
Content curation, social posting for clients.
Tried to use upcontent as a content discovery tool but it hasn't work out well due to lack of ways to make use of the discovered item. At its present state, it is more like a rss reader than a curation tool.