I am using uptime monitor for 3 or 4 months now and found my experience very pleasant. - The web UI is very fast, it feels like it's a desktop app rather then website - monitoring starts the second you launch it, no need to wait 5-10 minutes, which I hate is its competitors - monitoring interval is very small, I love it - it's free and I'm still using free version, considering to acquire subscription - it's feature focused and it's great. It does one job and does it good

I need just one feature - 30-second checks for free! 😁 Also, Uptime Monitor supports SSL certificates expiration alerts and status pages.