Crosswalk:
+no splash screen (cocoonjs has a required splashscreen unless you make a deal with ludei)
+has good potential if they can they can add all the feature requests, might improve with time?
+maybe better slightly support than CocoonJS?
-Android only
-apk file sizes are bigger than CocoonJS
CocoonJS:
+iOS and Android support
+much better performance in my experience
+has some support for IAP and ads
+smaller apk sizes than Crosswalk
-long start load times, memory problems and crashes if your project is too big because they don't do layout by layout loading
-Ludei's lack of clear pricing model for removing the splash screen is annoying (why not just have a subscription model like Unity or something instead of trying to do a confusing profit share plan with developers?)
I favor CocoonJS mostly but am crossing my fingers that a better alternative will come up soon (I haven't tried crosswalk lately but last time I tried it it just wasn't as fast and apk file sizes are too big).