Photoshop express and proaint are poor compared to snapseed and photogenie. And genial writing is very very poor. What android needs is a port of penultimate or Noteshelf, plus the Nik apps for the iPad. I would love either some decent apps for my galaxy tab or a 7" iPad.
Never owned an IPad, so I have no idea how various programs relate. Not a fan of "I" stuff personally.