Both!
I have had both since Wonka launch and like them equally for their own strengths.
Star Wars is my absolute favorite game. The combination of theme integration, shot variety and just pure adrenaline is unmatched, IMO. It really has that one more game quality. "I know I could have executed those shots better or moved the multiplier more effectively" or something that gets me to push start again.
They both can drain cheaply. It can be avoided on both but unsuspecting players will be like "what the heck, that sucked".
Wonka is pure imagination. Such a beautiful looking and playing game. Every shot is like butter. Easier, longer games IMO
With SW you get to choose your destiny for modes. Wonka is much more random. You can't really pick whats next like you can on SW.
Tons to do on SW but more to do on Wonka for sure. Not that it matters, I've had the game since launch and still haven't seen the back quarter of Wonka's modes. I think most people that hate on SW have never played one that is setup decently or they don't understand the basics of the game and what modes to pick when. A 2 minute overview from a friend of mine took me from being "meh" to the game to it being one of my favorites.
Build quality - JJP games are just built better. The cabinets are stronger and can't be flexed like a Stern game, it just feels more substantial.
Wonka is "prettier". The huge screen, rainbow of LEDs under 100s of inserts. Just spectacular.
Wonka seems to be more approachable to non-pinheads. My wife just loves Wonka and does not push start on SW as much (read not at all). Not sure if this means anything to you.
I don't think you can go wrong with either. I would have a hard time picking which one would stay. I personally like playing SW more but I suspect Wonka would stay due to my wife liking to play it with me.
For now, they are both bolted to the floor.