Quoted from Mr68:

Put a Powerball in your EM game. I've been trying to promote this for a few years now with little traction it seems.
Your game will play faster and bounce differently, almost like a new game.
Yeah, I know they're expensive, so just try one and see if you like it. I've done this on a ton of EM games over the years and all of the EM machines and mechs work perfectly.
For multiball games you can replace all of the balls, or just mix one powerball in for a random change up.
Also add Titian rubbers and away you go.

Quoted from paulace:

I love EM's so you can take what I say with a grain of salt, but one difference that I notice between EM's and newer games in particular is that the latest greatest SS games, though they have incredibly deep rulesets, have a definite path (often multiple paths) of progress towards a goal of achieving everything that can be achieved on the machine. A few of my friends that like the newer games are much better players than I am, and some are good enough that sometimes they get to the end of what you can accomplish, and they become bored with the machine. They talk about "beating" it.
I don't think this is true of early SS games - I don't think anybody really "beats" Firepower or Stars or Flash Gordon or Paragon. But something's changed about the complicated newer games.
I never hear anyone say they've "beaten" an EM. When our league plays, there are guys who can have a 40-minute game on Lord of the Rings - I have to go out and get a slice of pizza while they play. Nobody has a 40-minute game on Fast Draw or Slick Chick. Because everyone can easily understand the rules of an EM (heck, they're usually printed on the playfield), I have a much better chance of beating these very good players on an EM than I do on Godzilla. There's something about the simplicity of the goals on an EM that some people find boring, but I find endlessly challenging. It seems "purer" to me somehow because the goals are so simple. It's a great example of "simple" and "easy" not being the same thing.
For the record, I'm up to 7 machines - 2 Gottlieb System 1's and the rest EM's. Now if I can find a Strange World, I'm set!