I havent tried purchasing songs through this app and I dont plan to, so Im not reviewing it on that basis. I have my own large library of MP3+G zip files (ripped from karaoke CDs and downloaded from the Internet) and all I really want is a good iOS app to play them. If thats what youre after, trust me this is the app you need. Ive tried many others, including Karaoke Player, Karaoke Anywhere HD, and Karaoke Party HD, to name a few. I can make playlists, search for songs, and skip forward/back in 10-second intervals within a song, and the interface is clear and easy to use. It even separates the artist and track names in the song listing based on the way my zip files are named ("artist - trackname"). If it supported landscape mode in song list view, I wouldnt have any complaints.
Ive got the iPad loaded with 10G of karaoke songs. From there by audio cable to a simple Radio Shack 4-channel stereo mixer, to which Ive also attached a couple of Emerson wireless mics. Then from the mixer to a set of VocoPro PV-802 speakers. Done. Karaoke heaven.