I got a chance to use this product when it was in beta. I was setting all my cron jobs using crontab before using this product and it was becoming harder day by day. After getting my account ready, I moved all my cron jobs (Around 32) to ExternalCronJobs. It made my life very easier and I have now all my cron jobs with logs and I get notifications of failures of my cron jobs.
I am now their paid client using their hosted plan and quite happy with them.
I would definitely recommend this product to everyone.