There’s been a lot recent discussion on having a wide belt or drum sander in the shop. Since I’ve had plenty of experience with both, I can offer some insights.
The wide belt is without a doubt the better machine. But the cost is often prohibitive.
Drum sanders require more patience to operate successfully and, as many have pointed out, inevitably leave you with more hand sanding at the end. But they do a great job of getting panels flat.
When I was making chessboards, I put hundreds (if not thousands) of them through my Woodmaster drum sander and even though we still had to finish sand them on the bench, the time saved was huge.
The one thing I personally would never buy (feel free to disagree) is a multi drum machine. The time spent trying to dial in the two drums and get the second one to remove all of the scratches from the first can be maddening, especially with the rather crude adjustments typically found. It’s easier to just change out the abrasive on a single drum.