I've started experimenting with Swarm myself but I know one guy who has a histamine reaction every time I mention it. I haven't gotten (or really tried to get) a straight answer out of him about why it's a bad thing.

If you have a countable number of instances of a couple dozen services and one or two "lots of instances" services it seems like it should suffice just fine. And really, my brief sojourn into Kubernetes left me feeling like I bumped into road blocks for anything more complicated than that. Especially with sidecars, or if your tool chain uses multiprocessing instead of threading (Rails, Node, Python?, etc) to deal with concurrency.