I've been using UptimeRobot to monitor the sites I build and maintain for clients, and it's become a quiet but essential part of my workflow. The dashboard is genuinely simple to work with. Adding a new monitor takes under a minute, the setup is self-explanatory enough that I never had to dig through docs, and I was watching my first site within minutes of signing up. The main overview shows me the status of every site at a glance, and I can drill into any individual monitor's response times and incident history in just a couple of clicks.
The monitoring itself has been reliable. Checks run consistently, and the response-time graphs help me spot when a site is getting sluggish before it actually goes down, which has let me catch a couple of issues proactively rather than hearing about them from a client. I have alerts routed to email, and the option to add webhooks and other notification channels means I can plug it into whatever setup a given client uses.
For a freelancer managing several client sites, the value is clear. Knowing immediately when something goes down, instead of finding out from an annoyed client, is worth far more than what the plan costs. An unexpected benefit has been the uptime history: it's useful for showing clients that their sites are genuinely stable over time, which reassures them and reflects well on my work. Review collected by and hosted on G2.com.
So far I haven't run into anything I genuinely dislike. If I had to note something, the free plan's 5-minute check interval is slower than the paid tiers, so a very brief outage could resolve before it's flagged. It hasn't been an issue for my use, but tighter intervals on the lower plans would be a nice-to-have. Beyond that, I haven't used the more advanced features enough yet to speak to them. Review collected by and hosted on G2.com.