I've used the Shoulder Dolly to move all kinds of things, including refrigerators, couches, dressers, and more up/down stairs. I've never used it to move a pinball machine up stairs, but I wouldn't hesitate to do it. As with most tools, there's a technique to using this, and practicing makes it much easier. People who are used to using brute strength to move things usually don't see the point. I'm not a big guy so brute strength is out for me. I have to think about how to move heavy things, and this works great.

Here's the link to the manuf. with a video how-to:
http://shoulderdolly.com/products-2/consumer-shoulderdolly/