I've been fiddling with the latest Pixelmator update. It's pretty great. Even though Apple doesn't support external editors with Photos on the Mac (at least yet), Pixelmator can now access your full Photos library from inside the Pixelmator with its Photo Browser. They also drastically improved the repair tool. There is a video on the Pixelmator blog that demonstrates removing objects (and people!) from an image with almost no effort. It's definitely worth checking out.