Wheels come in different grits and bonds for a reason. 'Fine' is OK for finish work, but if you're trying to rough down a chipped chisel, you'll be there all day, or turn it blue and ruin the temper. To be honest, most bench grinder wheels seem to be pretty similar, regardless of brand. In my trade, we use a wide variety of grits and bonds, but that's on a surface grinder, doing precision finish work. Many of those wheels are inappropriate on a bench grinder (too hard, too soft, too fine, etc.) Ideally, you want a coarse/medium wheel on one side; fine on the other, and keep them clean and trued.
When I have a LOT of material to remove, such as putting a big radius on the corner of a piece of steel, I like a 6" belt sander with a coarse belt.
As for brands, a name brand like Norton will be great, but expensive. I have a Harbor Freight 8" bench grinder, and the wheels that came on it are very soft. Good for keeping the part cool, but they wear down fast. Places like MSC will have a wide variety of wheels to choose from.
