Been through a few different setups for stress testing — started with k6 self-hosted, then moved through a couple of paid services. Currently running everything through DDoSNow because of three specific things:

1) DNS TXT target verification. You can't launch anything without proving you own the target via a TXT record on the domain, and they re-check on every launch. Means I literally cannot accidentally point a test at upstream/neighbor infrastructure, which has actually been a problem for me before with looser providers.

2) Method coverage is complete. Layer 4 is the usual (TCP-SYN, UDP, ACK, GRE) but the layer 7 side is what sold me — HTTP/HTTPS flood works, but they also have proper browser emulation with cookies, headers, form input and per-step delays. Useful when you're testing how your CDN/WAF reacts to real user-shaped traffic vs raw packet floods.
3) REST API is clean and well-documented. I have it wired into CI so we run a quick capacity check on every deploy to staging, and a longer drill once a week against an isolated environment.

Annoyances — Starter tier only gives you 1 concurrent slot (you'll outgrow it fast if you're doing anything serious), and there's no SAML/SSO yet for team accounts. But for what we use it for (a couple of SREs running stress tests on our own services) it does the job.

Crypto payments which is fine, no KYC on basic tiers, instant tier swaps, cancel anytime. Take a look if you're shopping.