The meat of the lamb's shoulder is sweet tasting thanks to the streaks of fat that appear naturally in the joint. When buying, you need to ensure that the joint is boned to the degree your recipe requires - some need complete boning, others need part-boning. The pockets left by the removal of the bones are ideal for stuffing.
Retailers often sell the shoulder completely boned, rolled up and tied. You can cook this joint as is, or untie, stuff it and roll up again ready for the oven.
Shoulder is a good joint for roasting, and excellent when poached to serve hot or cold with pungent sauces based on herbs, spices and fruit.
You can cube the meat to make stews, especially exotic Middle Eastern and African recipes. Moroccans steam the whole joint. In Scandinavia it's served with sour cream sauce.