As someone who has previously used Balanced and played around with Stripe enough to get a feel for it, I feel like I need to chime in here.
Balanced initially reached out to me, and I initially somewhat dismissed them, because I didn't have the time to look in to their platform as I was busy building a marketplace product for which we thought we had already picked the payment provider for, PayPal.
However, few weeks later I decided to take the time to investigate Balanced's offering and I was quite simply blown away by what they had to offer at the time (since then their offering has significantly expanded). As a result, I decided to make some time to rewrite our payments to use their APIs, because they solved the one hard problem I had yet to solve, which is the payouts.
I distinctly remember that I had just spent the earlier part of that week going over the various alternatives to how we could handle payout, and none of them seemed optimal. While paypal certainly would've gotten the job done, it was far from ideal especially considering that our merchants would've had to sign up for a paypal account and the fact that they have a track record of mistreating individuals and businesses by freezing accounts and funds. The other alternatives I had considered would've been much more work to integrate with and would've probably eventually driven me up a wall.
This was the first thing that struck me as the truly valuable feature of their product.
When I actually began integrating with Balanced, my "developer relations" experience with Balanced has been quite the opposite. Heck, I had a phone call with one of the Balanced founders (Jareau) where he took the time to answer all of my questions and explain to me how everything worked. In addition, I was able to simply hop on to Balanced's IRC channel (#balanced on Freenode) and talk to their whole team right there and then in real time. When I had questions about any of the functionality, there would always be someone from Balanced's team available to answer my questions. I should also mention that even some people outside of Balanced (i.e. customers) are also helping out on that channel.
Yet again, I was impressed. I never had issues with getting the kind of support I needed from Balanced, they are very responsive and helpful in solving any problems I have encountered.
Not to knock on Stripe or anything, but I never quite felt like their product was suitable for the situation that Balanced is suitable, a marketplace that needs to do payouts (or nowadays I suppose anything that needs to payouts). I feel like Balanced really hits the sweet spot when it comes to payouts, and they continue to work hard on making sure that their product is the best that there is in that category, and I certainly think that is the case right now.
One thing that I think bears mentioning is the fact that Balanced is also very receptive to customer feedback. In my experience, they are constantly weighing out what's the next thing they should be building/doing to make their customer's lives easier, and so their process is very much driven by the feedback provided by their customers (check out their API docs github to see the process in action, https://github.com/balanced/balanced-api/issues)
Overall, I do think that Stripe and Balanced to have overlap in what they do for you (charging a credit card), but I also feel like both of them have their strengths in differing features. I do think that for marketplaces that need payouts, Balanced is vastly superior because of the feature set that they have built, but if you had to something like subscriptions, then Stripe would be the way to go.