This is an i450 + a PictBridge connector on the front. That's all. This new type of USB socket is dedicated to direct printing of photographs from cameras of the same standard. The quality, speed, and ink cost are the same as those of the i450, so refer to the latter to get the results for this i455.
This is quite simply an i450 with card readers on the front for printing photos without having to go through a PC.
Take a i470d, add a PictBridge connector on the front and you have the i475d. Unless you absolutely must have the brand new interface for digital cameras, the additional cost doesn't really seem to be justified.