Disclaimer: I like to see gemstones in motion; so to formulate my opinion, I went to Wink's screencast videos and looked up the ones that show off your two cuts (elongated cushion and LucidaZ).
I gotta say I'm quite drawn to the elongated cushion. I like its softer lines over the angular ones of the LucidaZ (and my bias is obvious since I have an oval shape in my e-ring). And I also like the smaller sparkles of fire and bigger flashes of white that come off the elongated cushion compared to the bigger chunks of dispersion and smaller chunks of white from the LucidaZ. I think that makes the elongated cushion more diamond-like and less CZ-like to me.
Another vote for the elongated cushion here. I have a 9x7 cushion in the lightest yellow color like the one Emanuela posted the video link for. Of the Wink stones I purchased that was my husband's favorite as well.