The Epic 4G has the most versatile keyboard of the three. It has a dedicated row for numbers and several special keys (search, back, home, smiley, etc.). The keys themselves are chicklet-style, reminiscent of Apple Macbooks and Sony Vaio laptops.
The BlackBerry Torch has the traditional BlackBerry qwerty that has been around on high-end devices since the BlackBerry 8800 World Edition. It is a top quality keyboard with a nice weight to it and typically has a low error rate. Those who are already familiar with BlackBerry will love the standard feel.
The Droid 2 keyboard is the worst of the three. The keys are too flat and non-distinct and there are no special keys other than the arrow keys. The Droid 2 keyboard is better than the original Droid keyboard, but that's not saying much. Most of the people I know who have a Droid bought it at least partly because of the physical keyboard. But those same people report that 90% of the time they never use it, since it's so bad.