I've played them all.
Future Pinball: Gorgeous full 3D graphics but terrible physics spoil many tables (some are worse than others). Doesn't use ROM images so the rules and sounds on solid state tables don't always work the way they should. From what I understand the developer has lost interest in this and the core software will probably never be updated again. Free.
Visual Pinball: Graphics are 2D, so no viewing-angle controls and tables are a mixed bag visually. Physics are generally much better than Future Pinball. Integrates with PinMAME, which means tables use the actual ROM images from solid state machines so everything works and sounds exactly as in real life. Free.
Pinball Arcade: Gorgeous full 3D graphics, the best physics of any of them. However, no control over the table settings, and you are limited to a handful of tables as compared to FP and VP which both have hundreds of tables available. Poor, limited nudging controls. No Windows version. Not free (but reasonably priced for the quality in my opinion).
Zen Pinball: Doesn't offer real-world tables so it doesn't interest me much. Cool special effects and reasonably good physics.
If you want to play DMD pins on a tablet, Mac, or gaming console, Pinball Arcade is the best choice, provided the game you want to play is one they offer and you don't mind coughing up a few bucks. If you want to play DMD pins on a Windows PC, Visual Pinball is the best choice. If you want to play EM pins on a Windows PC, Future Pinball is the best choice (although there are some good-quality EMs in Visual Pinball--check out Jacks Open).