Seems to work just fine...

Despite the few negative reviews, I took a chance on this app and it’s iOS verisons to share between all of my Apple goodies. I’ve had no issues — shared PDFs and photos to and from all devices - never failed; worked like a charm. I gave it 4 stars instead of 5 only because the sharing does not work in the background. If the iDevices go to sleep or close out the Instashare app, it doesn’t work. Get this work at any time, as long as the devices are powered up, and it’s a full five stars.

Listerart about Instashare - Transfer files