I, too, like them a lot, and I worry that eventually they're going to be "the internet" in the same way that Twitter became "the communication platform" or AWS became "the infrastructure".
We're going to see days when something goes wrong on Cloudflare's end and disrupts their whole CDN, and 2/3 the internet is going to break.
Still, at this point they're absolutely a net positive, and seem like a good steward. They even once replied to one of my e-mails saying "Based on what you've said about your use case, you should just use our free plan which you can sign up for on our website".