Spice – Difference between ground cloves and clove powder

They're completely different.

Cinnamon is warm, woody, hot, sweet, spicy, bark. Nutmeg is eggnog. If you want something to taste like Christmas, use it.

They're both delicious, versatile, and can work well together.

By volume, you can use much more cinnamon than nutmeg. Nutmeg is "a dash of" kind of spice, while cinnamon can be mixed with butter or sugar and slathered on basically any pastry. (Equivalent amounts of nutmeg would probably get you stoned, but that's for another forum).

Also, nutmeg shares flavor notes and aroma with allspice and cloves.

Yes, you can detect the difference. How much of a difference will depend on the quality of both the imitation and of the real thing.

That said, it's difficult if not impossible for me to pick out the differences in baked goods. So I keep both around, and use the (much cheaper) imitation stuff for baking, and the real stuff for sauces, icing, custards, milkshakes, etc.

Incidentally... In a pinch, bourbon makes a half-decent substitute for vanilla.