As one of the Founders of buddybuild, I'd like to perhaps also provide another perspective on this specific thread.
We certainly don't think of buddybuild as a closed ecosystem.
In fact, our users are able to customize buddybuild infinitely to meet the needs of their workflow (details can be found here: https://www.buddybuild.com/blog/customizing-the-build-proces...)
Further, while buddybuild is favored by thousands of because it can can auto-provision iOS devices for you on the fly.
Meaning, you never have to deal with provisioning profiles and UDIDs ever again.
We also care deeply about making sure that teams can involve and engage their end users as part of the development process. One of the reasons we built buddybuild is because of the frustration sending builds to our users... AND then never hearing back from them. Phones are great devices for "consuming content", but it became obvious that the physical form factor of the device tends to result in infrequent feedback which was often ambiguous.
So, we build an SDK that gives you high quality and actionable bug reports from beta users. With a simple screenshot, testers can file bug reports that include graphically annotated screenshots, feedback notes and their device metadata.
We also have a feature called "Instant Replay", which lets you watch a video of the exact steps required to reproduce a crash. Instant Replay works in conjunction with our Crash Reporting solution to offer you both the exact lines of code that caused a crash as well as the exact sequence of events that lead up to it (https://www.buddybuild.com/blog/introducing-instant-replay)
Thousands of teams with fairly complex needs use buddybuild every single day. They teams like Slack, Meetup, FireFox, Wordpress and others..
You can read why they made the choice to use buddybuild here: http://www.buddybuild.com/customers