They are all snap shot camera. No special functions but just easy to use.
W1 & R51 are same level 5.0M pixels, but stupid look. Also, Sony will cost more with it's brand name and most of pro-users comment 'Sony' picture is too 'RED'.
Z40 is one of the hot item now with smart looking and quick response. But only 4M pixel, for 4R, it should be enough.