My advice? Don't pay any attention to what anybody here says. Play as many pinball machines in person that you can that seem to appeal to you for whatever reason, and buy the one you keep coming back to when you want to play. Many people will tell you what a great game Twilight Zone is, but for me, I HATE it. Don't know why - I loved the show, the ride at WDW - just don't like the game. I'm ready to walk away after the second ball. Buy what YOU enjoy playing. Buy it used from a reputable dealer who will deliver it, set it up, and service it after the sale at a somewhat reasonable price. Use the money you saved buying used to start looking for another game.
Pinballs are a little something like what they say about wives - you don't marry the girl you think you can live with. You marry the girl that you know you absolutely can not live without! If you haven't found that yet with a pinball and you are looking at spending $4000, $5000, $6000 or more, keep looking!