Just a few more items...
Yes, the Roland has more pads, but ZERO content is provided for them.
There is no vocal harmonizer.
There is no text display.
There is no CDG player.
There are no usable break/fills; though some intros work for one.
The Korg has fewer programmable buttons, but the rows of sliders can be programmed for just about anything. There are three sets of factory presets, two sets fully programmable and one set for midi file use.
The Performance Bank is limited to 100 entries, before you have to change banks. That is a real step backward from the BK7m. Also the Performances are not sorted; if you want them in alphabetical order you have to do it manually, which takes five button pushes per entry.
There is much to be said for the EA7, and it is a real bargain in that price range, but it is no match for the P4X. Nor should it be, when you compare prices.
What the EA7 is--a great lightweight arranger, with excellent styles, drums and sounds. It has a great number of operational features. The OS is difficult until you become familiar with it, but no more so than any other brand.