Whenever I go out for Korean barbecue—the style of cooking where your meat is grilled tableside beneath giant exhaust vents—I always wish the marinated meats were less sweet and much spicier. Bulgogi, in particular, is usually so sweet that I skip it altogether and stick to less sugary cuts like marinated short rib.
At home though, you can easily make the marinades to your liking. Pear juice or puree is traditionally used in Korean meat marinades—the juice not only adds sweetness but also works to tenderize the meat. I've watched Korean friends and mothers use pineapple juice, apple juice, and even soda in lieu of pear juice, but I prefer the pear.
There are many variations but the two main kinds of marinade (spicy and non-spicy) can both take pear juice as well as soy sauce, sugar, minced garlic, sesame oil, and mirin. The spicy marinade differs mainly in its generous amounts of either red chili pepper powder or gochujang, which is a red pepper paste of red pepper powder, garlic, soy, and sometimes sweet glutinous rice. If you don't live near a Korean market that sells gochujang, you can make a very decent replacement by combining red chili pepper powder with finely minced garlic and soy sauce.
It's a lot of fun to place an induction burner on your dining room table with a cast iron skillet or griddle on top, and let your guests grill their own meats as they would in a Korean barbecue restaurant. If, however, the smokiness is too much for comfort, then quickly pan-fry the meats in the kitchen or broil them in the oven instead. (There is, of course, the option of moving the operation outside to your grill, but you'll want to make sure the meats are larger and cut in thicker pieces so they don't slip through the cracks of your grill grate.)
Serve with lettuce leaves to wrap the meat and an assortment of seasonings and pastes for garnishing. Sesame oil, soy sauce, more chili pepper paste are the classics, and at most Korean restaurants you'll find soybean paste too. If you're using very high quality meat and wish to enjoy its simple flavor, then salt and pepper is all you need.