Working with churches I have learned two things. The first is that it is nothing like the sports or broadcast market at all! The second is that no 2 churches needs are alike. All in one systems are usually designed for a specific purpose. Sales people will tell you other wise. Because of this it is important to know exactly what you want to use these systems for and how you want to use them. Design a workflow and make sure these systems will work the way you want them to.
I have used a couple of all in one systems and have seen a couple of different issues with them. The first is that they are usually software based or at least has to do some type of processing that causes delay. The second one was that it was designed for a one man show.
I was working at a church and we bought an all in one system that switched sources, acted as a CG for song lyrics and played videos. We found out that it was very difficult to cut cameras and run song lyrics at the same time, the system didn’t want to allow it. Videos had to be encoded into a special format that sometimes could take a long time depending on the video length. Without giving all the details the system couldn’t handle doing all of the things we wanted to do with it and it consistently crashed.
It is much better to purchase gear to do one task rather than multiple in the same box. The shows will go much smother and if one piece of gear fails the entire system won’t fail. In my opinion Churches needs stable systems.