I love this little printer. It does the job well for what it is and how much it costs. I looked into several different instant printers and chose the Step Slim Instant for the small product size, the small photo size, printer price, and price-per-photo price. The quality of the photos is fine for everything else you get with this product.
The actual printer is so small that it fits in my pocket, and the photo prints are a little smaller than a business card so it fits perfectly in my wallet. Those I've shared photos with are so happy to know these are also stickers! They cost about $0.50 per print which isn't bad at all, and the printer itself prints decently fast.
However this printer and paper is on the cheaper end - so the photos aren't exactly very clear or vibrant. It's perfectly fine for the price point and convenience. It does require the app (and on Android, this app requires location permissions) for printing, but the app is fine. A friend downloaded the iPhone app and was able to print through my printer this way too. I've noticed this printer seems to print iPhone photos better, and struggles with the quality of printing any digital art. Must be RGB to the ZINK style printing - purple tones don't come out very good this way.
I'm very happy with this little printer and haven't had any trouble with it jamming or printing. It does get warm/hot when printing continuously and will pause longer between prints depending on how hot it's gotten. It does print 'fast' overall though. I'd recommend this printer to anyone looking for a lower price point both for the printer cost and price-per-photo. However, make sure to check reviews with images of the photo quality to understand the quality trade-off. The photos aren't vintage-looking, and you can modify your photos in the app too to make them more vibrant or have more contrast. The quality is very decent for the speed and price point you're paying.