I would say WOZ, WOZ and WOZ ! I'm a little biased there because I have one and enjoy it more every time I play it, but between the depth of the game, the number of shots, the ability to stack modes, the lights sounds animations, the multiballs, a short term goal (kill the witch), a long term dream (sotr), there's just enough to keep going at it and try something new.
I also like the open approach to the modes , how they can be triggered in any order, and stacked. It has some fast shots, some more technical ones and even doors to shoot which feels like a small scaled MM.
They're really is a lot to like about WOZ