Lee Kum Kee's jarred sauce is good and very easy to use with results much like the restaurants.
I've made it from scratch successfully but the recipe you used is weak on the required dark earthy flavors that contrast against the sweetness.
Hoisin sauce is only part of that battle. You also need dark soy sauce and bean sauce though hot bean sauce is a fun twist if you like hot food.
Sure, variations exist. The five spice powder is not particularly traditional though it shows up in plenty of recipes. You'll see different sweeteners from brown sugar to honey. Ginger, sesame oil show up from time to time too.
If you want to do it from scratch, this is how I did it though now I always use the LKK jarred sauce.
2 tablespoons chicken stock (water will do if you must)
2 tablespoons dark soy sauce
2 tablespoons hoisin sauce
1 tablespoon bean paste--hot bean paste is a fun twist
1 tablespoon ShaoHsing wine
1 1/2 tablespoons honey
1/2 teaspoon salt (I skip this)
1 large clove garlic, minced
a few drops red food coloring
Mix this all up, will cover about 2 pounds of meat. Marinade about 2 hours minimum though more is fine. The best meat for this is strips from the pork shoulder as its fatty enough to remain moist. Other cuts work but can be dry.
Put a baking pan of water on the lowest rack setting. Set another rack in the middle or upper third of the oven. Set the oven to 350. Lay the meat directly on middle rack over the water pan. The pan of water catches drips that otherwise burn and smoke terribly in the oven.
Bake 45 minutes in the oven with a bump up to 400 for the last few minutes to set the glaze.
The rack you cooked on will be a mess. Soak it in water for a while and it cleans fairly easily.
You'll be tempted to grill with this. It's very high in sugar so indirect heat is the only way to do it with a quick finishing direct heat grill to set the glaze. Smoking also works even better IMHO.
