It's great. I've used it once for an electric blanket for chilly camping and it worked great. Turned it on for maybe an hour and a half before we got in bed, so it was toasty warm when we got in. It knocked off about 30% of the battery. Mostly I've been using it to power my notebook when I'm working remotely.
I wouldn't really say there's any con to it. It all comes down to your needs. It is on the lower-powered end of things at 240Wh and 100W max output, so you're not going to be running an electric kettle off it or anything like that with a higher draw. But it's great for lights, personal electronics, short runs for an electric blanket, etc.
It's also super small and lightweight. Enough so that it's able to just stay in one of our camping boxes, which is awesome. That being said, I'm very much considering getting the Jackery 1000 they just released - especially since they've got a $200 discount on it right now. It's definitely too big and heavy to live in the camping box but you can run just about anything off of it.