I have Pandora One and used to use it on my iPhone all the time with no problem.
Ever since I switched to the HTC One X, it can't even make it past 1 song without stopping, "Buffering...", and just skipping to the next song. It sometimes even skips 2 songs and spends a long time "Buffering..."
I have the One X, and Pandora works fine with no issues. So unlikely its an issue with the app needing to be updated. Try uninstalling Pandora, and re-installing. Also, you sure network speed is not an issue? Does the problem occur on a decent WiFi network?