I highly respect the folks at GMI (Global Mapping). They do quality work on maps and more, based on in-depth research, and they desire to do it at affordable prices. They recently surveyed a few thousand missionary recruits, asking them for input about the sending agencies with whom they were in touch. You can read their results if you’re willing to complete a [very] brief survey about a great resource they’re promoting, authored by Patrick Johnstone (“The Future of the Global Church”). I didn’t think the survey was at all burdensome. And I’m still delving into the stuff they learned from the recruits. Worth the read. Here’s the link to start the survey. Good luck.