Our Church uses ProPresenter for all our sites and student camps. Ultimately there will be a learning curve moving from anything else, but really it is pretty easy.
In our case we have a staff person who sets up the songs and talk slides then they are exported into a bundle which packages any media together. This means the volunteers just need to import the bundle then run it like almost any slide show without needing to know the intricacies of program (though we do try to teach and empower our volunteers so they can make changes if needed).
There is a phone remote program that can be linked to the computer to allow your pastor to continue to be the one in charge of when slides
advance.
ProPresenter will import
PowerPoint files fairly well with the exception of animations. We still have a lot of teachers who use
PowerPoint and we import them each week, though they have all been warned not to use any animations.
There are a lot of great features if you want to use them. We have confidence monitors for the musicians which will show the next slide and ignores any backgrounds to create a simple white words on a black background.
We also have an communications module that lets us use
DMX from the lighting
console over
ACN to trigger backgrounds so our lighting and backgrounds change in sync. We also have a
midi setup to allow Ableton Live to trigger a video on the same backgrounds machine so a special video is in sync with audio tracks the band uses. The advantage there is even if the video
system died, the band would still have tracks and click so they could continue (in the past we had a video accidentally stopped by the TD with a stray
hand which brought the service to a crashing halt).