When I brewed the first time with Fermentasaurus I kept the wort in the cellar, and it's too cold for it there (about 14 C), insulated jacket keeps it almost 20 C which is great for top-fermenting (18-22 C).
It is also great for keeping fermentasaurus from scratches between the batches.
The quality of this jacket is impressive. It's surprisingly thick and it did a really good job of smoothing out the ambient temperature changes during fermentation. It's a bit tricky to put on or take off (although much easier if the fermentasaurus is empty) however a bit of planning means it's no big deal. I'm sure it's not the smartest plan, but for small moves it was possible to move the fermenter with out opening the jacket by bear hugging the whole assembly, mainly so I could **** it on my trolley for easy transport. Otherwise you need to unzip it to get at the handles, and as the whole thing can be pretty heavy its at least worth thinking about. Very happy with it.