I personally use Sprout Social and manage 56 different brands from a single interface. It not only allows we do outward posting across all the major platforms with advanced scheduling, I can also get very detailed insights into the engagements of my post and all the essential demographics as to the audience. I really love that part. I am able to really focus my interactions for the different brands based on who is actually interested and create real conversations not just standing on a soapbox and shouting into the void.
I prefer Buffer App. You may find another solution with MORE features, but I think Buffer has the RIGHT features without complicating the app/user interface/posting process unnecessarily.
I've tested every system I could possibly find (and am constantly on the lookout for the next best thing to aggregate and streamline all of my social media management) and so far, the best thing out there right now is Sprout Social. It's super reliable which is # 1 for me, and has the most integrations. The reporting feature is also top notch. Stephanie who works with me actually did a really good post comparing Sprout Social with Hootsuite which you should check out: http://www.neworleanssocialmediaconsulting.com/sprout-social-vs-hootsuite/
I use Buffer for content scheduling and postings & hootsuite to monitor brands on social channels.