If you can find managed Plesk, somewhere, it could be great, but I had a season where I tried to manage it, myself, both for my projects, and my client projects, and after jacking with it for about a year, it just became too cumbersome to deal with.
(and expensive)
cPanel is tried-and-true, but the client level management portal is WHM, so you're kind-of comparing two things that aren't quite the same.
If I were you, I'd just find two highly reputed services that are MANAGED.
Test each of them for a month, and then go from there.
I will say that I don't like WHM very much, but it depends on how well your service manages it, and offers support for it.
Plesk has some higher quality features, but it has to be configured properly, and there are a bunch of marketplace extras that make it progressively more expensive, so if you can find a good managed service, then maybe it'll be better than my experience.
Actually, I don't even use Wordpress anymore, except for a couple old projects.
I only use https://bootstrapstudio.io/ and https://www.blackhatworld.com/seo/ivans-tumblr-blog-theme-for-seo-and-pbns.1370329/#post-14840537, now, and it's a much better life! 
Best to you, dude!
