I was concerned that this tool might be too good to be true, but as it turns out its amazing! Set up took about 5 minutes through the AWS UI. We then used the UI tool from LeanerCloud to set up the tags and instantly started seeing spot instances appearing. We're looking at around £15k USD saving per year at present and this is with the default optimisation (newer instances) rather than for cost. The only minor hiccup we had is that we use an instance refresh to replace our instances, and auto-spot was interfering with this process on deploy. As part of our deployments we set a tag to temporarily pause autospotting and then restore after the instance refresh has completed. Christian was very responsive on this and the functionality was added to the next release.