Good documentation, UI, many, many plugins and fair pricing (IMO).
(Im not affiliated with in any way other than using their product on a pet project with many moving parts).
As far as Datadog goes, it's the most team friendly dashboard system we've used. We had a specialty monitoring system for one application stack previously, and no one made custom dashboards there or even just looked at the data. Now we've got custom dashboards out the nose and we're gradually consolidating to a "best of" dashboard for each service.
Are you affiliated with Wavefront?
(I've learned not to trust numbers that seem too good to be true unless they're contractually obligated.)
Wavefront doesn't publish pricing, but if we take Librato's pricing as a general indication you're talking several million dollars a month.
I used it up until two months ago when I left that job. There was 2000~ servers monitored I think.
I'm asking because I will be designing a similar page soon (that's also billed per host) and I'd like to avoid the same mistakes.
1. VERY clearly state that when you sign up for the service, then you are on the hook for up to $18*500 = $9000 + tax in charges for any month. Even Google compute engine (and Amazon) don't create such a trap, and have a clear explicit quota increase process.
2. Instead of "HUGE $15" newline "(small light) per host", put "HUGE $18 per host" all on the same line. It would easily fit. I don't even know how the $15/host datadog discount could ever really work, given that the number of hosts might constantly change and there is no prepayment.
3. Inform users clearly in the UI at any time how much they are going to owe for that month (so far), rather than surprising them at the end. Again, Google Cloud Platform has a very clear running total in their billing section, and any time you create a new VM it gives the exact amount that VM will cost per month.
4. If one works with a team, 3 is especially important. The reason that I had monitors on 50+ machines is that another person working on the project, who never looked at pricing or anything, just thought -- he I'll just set this up everywhere. He had no idea there was a per-machine fee.