I only used it for the last few months, and while it seemed like a gimmick at first it quickly grew on me. I had a tab group for each programming subject I was working on, with lots of documentation open. Next to these I had groups with things like music streams and Wikipedia searches. For me it was a neat way of organizing, and making sure I could start up exactly where I left off with every project.
They recommend switching to Pocket, but it feels like a mismatch. I thought Pocket was a bookmarking/read later service, while Panorama was about workspaces. It would be great if they could release Panorama itself as an addon.