Anecdote only...

I'm a web dev, and I once encouraged a UX designer I knew to get a job at Datadog because I enjoyed using it so much as a customer. When they asked me why they should apply at the smaller Datadog over NewRelic, I replied simply that "Datadog sells to engineers, NewRelic sells to management" -- a statement that I've found to be true in my personal experience. (This person did end up getting hired, and they told me that seems more or less true from the inside too, but that culture is slowly changing as Datadog gets bigger, sadly.)

Datadog has awesome DX. Most basic analytics and reports are really easy to set up, especially compared to their peers 5-10 years ago. And their end-user (well, report viewer) UX was really good compared to their peers back then, with clear dashboards, really to use synthetic testing with a built-in recorder, etc. And they were affordable to try. Spinning up a test took like 30 min and was either free or like $20 depending on the services you needed. I think of this as the Vercel/Cloudflare model, just applied to monitoring. By that, I mean they provide the basics for free or very cheap, allow devs to learn and self-install in minutes, use it for months for barely anything, and fall in love with the service enough to sell it up to management (who often only reluctantly agree because it's not AWS, not enterprisey enough, whatever). These are the companies that rely on having a good relationship with developers. When I think of Datadog, the primary emotion I feel is joy with a bit of excitement.

On the other hand, there are companies like NewRelic (but also Oracle, Salesforce, arguably AWS, etc.) who are too big to care about small teams and individual devs. They chase enterprise contracts with other big players, and don't really care about DX or UX because their real customer is management, not engineering. They make money by appearing respectable enough in that "nobody ever got fired for choosing NewRelic" kinda way.

I've had the misfortune of having used NewRelic at previous jobs. My god, I'd never seen such slow, bloated software with atrocious UX and user-hostile, opaque pricing -- at least back then. Especially comparing the two when Datadog came out, it was a night and day difference, like comparing Excel 97 to Google Sheets way back when. These days I think NewRelic is a little better, and I see they also have a free tier now. But I used it as recently as earlier this year and it still seemed way more bloated than Datadog. It's probably more featureful in some ways, but most of that just feels like bloat unless you're a hyper-scale company. I've only ever seen NewRelic at bigger companies, like the last Fortune 1000 one I worked for, or integrated into third-party offerings (like Pantheon, an enterprise Wordpress host who's otherwise amazing). The primary emotion I feel anytime I have to login to NewRelic is a sense of overwhelming dread.

They just have very different strategies and approaches to software, IMO. Of course as a dev I prefer the more "indie", agile companies like Datadog, but I also recognize that it's probably also only a matter of time before Datadog simply becomes the next NewRelic. I just hope we get a few more years out of it before enshittification sets in...