It's been growing on me for quite a while now.
I've had my WOZ for 2 years, I love the game, I love the theme but it's also turning slowly into a frustrating experience as I'm nowhere close to completing all the modes, and some of them feel out of reach.
In between I bought a TSPP, which is my first standard body, I started realizing that it makes a huge difference in play, in speed and "frenzy" once the ball hits the lower playfield, it feels like playing pinball on steroids, even on a TSPP that is far from being the fastest game around.

Then comes DI, I hated the game for a while, I would barely play it on location and always felt bored shooting randomly and just trying to keep the ball alive. Until a day where I saw the light, played an awesome game, and started to really get into it, read the rules, and really got to enjoy the game. I'm actually a much better player at DI once in a while on location, probably 150 games or so, than the 1500 games I've put on my WOZ without really getting any better.
Same with TSPP, and I must say playing good games almost everytime is very rewarding and a good reason to want to play more.

So here I am, wondering if I should part with WOZ and get a DI, I know I will always enjoy playing WOZ, but the growing frustration that comes with it, makes it tough to start a game with the hope of nailing it.

Thank you all for your replies, I need to sleep on it a bit, I'm really going back and forth with letting it go or not. It goes up and down often related to how well I do on the game I must admit, but I went out to play DI again this weekend, and I don't think playing pinball gets more fun than that.

Getting both was where my head was headed actually. I can sort out my room and fund problem by letting go my TSPP, but my kids are totally against it, and I doubt the DI theme will appeal to them as much as The Simpsons do. So it's a catch 22 for now, I'll leave it there for now, eventually they'll grow out of The Simpsons and I'll have a shot at getting a DI.

For now I'm just happy to have pinballs in my house, it makes the days much easier !