Instead of chilling out while the essences seep into your skin, you'll first have to turn on the device, pair it to the app (which is consistently quick) and select the mask you're using. During each session, the companion app guides you through the process and explains what the puck is doing while you rub it all over your face. It's all very comforting and makes me feel like the device is actually doing something more than a regular mask. The heat, in particular, is pleasant, although sometimes it can sting if you let it linger on one spot.
It only weighs 146 grams, about the weight of an iPhone 8, but as I dragged it all around my face and neck for 90 seconds, it started to feel heavier. Switching hands usually alleviated the strain, so it's not a huge deal. I typically used the UFO standing up, but on the rare occasions when I'd lie down and use it for a more relaxing session, the weight was less of an issue. But then the risk of accidentally dropping the puck was real, and potentially painful.
What I struggled to get used to was scanning the bar code of each mask's packaging. The first time I used it I had actually thrown away the sachet and finished attaching the mask to the puck before launching it in the app. I had to gingerly pick up the packet from the trash, avoiding contact with food scraps from dinner, and point my phone at the bar code to move on.
Scanning that bar code does nothing other than tell Foreo you're using a mask it supplied -- you can't use masks from other companies. It doesn't automatically tweak settings to optimize for the type of treatment you've picked, and you have to select whether you're using the day or night mask before you get to the scanning page. This seems like an oddly overbearing feature with no real purpose.
Otherwise, the app is actually pretty good. I like that there's a brief pause after you hit the start button before the puck starts heating up and vibrating, so you can prepare yourself. In general I found that there was less essence left on my face compared to when I use traditional sheet masks. I squeezed out every last drop of the fluids from the sachet onto the disk, and at the app's suggestion, I repeated each 90-second cycle once to get all the juices into my skin.
According to Foreo, it "uses your skin's natural reactions to heat and cold as well as signature T-Sonic pulsations to ensure you get the most out of every mask treatment." Basically, your pores open up in reaction to heat and better soak up the goods.