alt Hacker NewsBetter Stack got on my disapproval list, for spamming me with a series of automated sales emails 15-20 minutes apart, which seemed designed that way. "One more thing.", etc.
They should've sent one welcome&upsell email, not several. And not abused contact info that was intended to reach me reliably and promptly.
For my immediate very simple need, Uptrends didn't spam me, and so far they've reliably and promptly notified me whenever my site is down even briefly (e.g., rebooting for kernel update), so they'll be getting money from me as I grow. https://www.uptrends.com/
Sorry to hear. I didn't have that experinece; it's been pleasant for me (there was a billing snafu while they changed their plan structure but it was resolved with a support email) and their monitoring has been very reliable since I signed up a year ago. Their service also seems to be better (4 checks/locations vs Uptrend's 2.)
Anyway, tl;dr is I never had an issue that resulted in not getting alerted about something that I needed to be alerted about, which, above all else, is the point of their offering.