Well spotted. Installed on my Galaxy Note ok
More one star than five star reviews, but I'll give it a go...
Mainly down to WiFi only streaming, and the amount of adverts and a few complaining of playback stopping and returning to the menu screen.
The adverts are annoying, but I watched several programmes on both my Nexus 4 and 7 yesterday and didn't have the playback/menu issues and found he PQ better than iPlayer (which can be shocking at times)
On the Samsung, I have hand installed flash (there is an android archive on the adobe site) and use this from firefox to access the iplayer. Vastly superior to the iplayer android app. I am running android 4.1. I bet this would work on the Nexi