Electric Drill

Ideal for polishing rims and workpieces with plenty of nooks and crannies.  Also ideal for polishing something where you need to take the tool to the workpiece (because it's large and/or heavy).  Use a Blokes Gear Drill Kit - with either 50mm or 100mm dia wheel on supplied spindle.

Polisher

Still has the portability of the drill but enables you to use larger polishing wheels (up to 200mm dia).  Therefore is ideal for larger projects e.g. truck tanks because the bigger wheels will last longer.  Use a Blokes Gear Polisher Polishing Kit supplied with a M14 Tapered Spindle.

Bench Grinder

Ideal for smaller projects, i.e. where you can bring the workpiece to the tool.  Grinder can be setup with one wheel (as shown above) or with wheels on both sides.  Wheels on both sides enables you to have sisal on one side and calico on the other - ideal as you don't have to change the wheels over.  Use a Blokes Gear Bench Grinder Polishing Kit supplied with one or two Tapered Spindles.