Recommendation for System Status Monitoring

Who has a good recommendation for system status monitoring?

Our Appian-based application relies on several connections to outside organizations.  Having a real-time system monitoring dashboard would be very helpful and I have started research on third-party monitoring services.  Chief interest includes up-time and connection degradation with the ability to have a custom dashboard that supports planned outage notifications. 

There are many solutions on the market but wanted to engage the Appian Community for any best-practices or recommendations for system monitoring.  Light research revealed the following: 

https://www.uptrends.com/

http://www.alertbot.com

https://www.site24x7.com 

... there are many others. 

Does anyone have experience with these?

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