Garlic Powder vs Garlic

Both may be preferable as they provide different garlic flavours.

• Fresh garlic is sharp, and has bite. It tastes fresh, and works especially well with other bold flavours and fresh ingredients.
• Granulated (roasted) garlic is garlicy, but nowhere near as sharp. It tastes more like the prepared garlic flavour we've all become accustomed to. It's a mellower, deeper flavour.
• Roasted fresh garlic is garlicy, mellow, and deeper than either granulated or fresh garlic. It's brilliant in smooth things like soup or mashed potatoes, and is also a much deeper flavour on a pizza with other roasted things.

One of the coolest things about these different forms of garlic is that you can use them together to pack more punch. Not only can you combine them, but you can add them at different times in a preparation to layer the goodness in interesting ways.

"Preferable" is all about taste, your (and your guests') preferences, and depth.

When I make pizza, for example, I use both marinated garlic and chopped fresh garlic. Sometimes I'll even add roasted garlic over the sauce, especially if the pizza has sun dried tomatoes.

Normally I'd say no, as I love garlic and use lots of it. But, there are a few cases where it might be handy.

1. Spice Rub (This would be my main usage of it. It is less likely to burn and I find the flavour gets "in" to the meat better).
2. Marinades (Alton Brown prefers it as it disperses more evenly)
3. Sprinkling on stuff like popcorn

More here.

If you just want for the taste, go for garlic powder and you wont get chunks that give powerful taste when eating.

If you want the texture as well, real garlic would be a better solution and has better aroma.

The only reason to use garlic powder would be if you're in a hurry. All the advantages of garlic powder can be attained using fresh garlic, albeit this can be some work and is not always worth it.

For example if you want to totally mix the garlic into a marinate you could soften the cloves in the oven and when they get soft squash them into the marinade. This will add a good 20 minutes to your cooking time, and a small improvement in taste.

So whenever you're using garlic powder you are being lazy, but most of the times you'll get away with it more easily then taking a short cut with fresh garlic.