I use WpVivid to create a stage at times to test an upgrade. I might even give InstaWP a spin to migrate a page to it for quick debugging. Although, after testing it for a bit and watching some walkthroughs, I think it will be most valuable to me in testing plugins and themes when making a choice for an existing page on what to install or finding the best solution. With InstaWP you don't need to worry about what the plugins, you end up not using, have left behind. Just spin it down, and restart. Another thing that might be beneficial are the two included pages with retention. I'd like more of them, but even the two could be a great whiteboard for quick shot ideas that might need a permanent home down the line… but a little more time to develop than 7 days.

Overall happy, and I think I heard something about an investment from Auttomatic in this particular SaaS. Either way, great work and service.