Buy the KitchenAid Classic K45SS if you bake cookies, cakes and the occasional loaf a few times a month, your kitchen is small, and the saving over the Artisan can go elsewhere. TechGearLab ranked it second of ten mixers and named it best for beginners, and nothing about its body, hub or controls is second-rate. You give up the handle, the shield, one dozen cookies of headroom and most of the color chart.
Buy the KitchenAid Artisan KSM150PS if you bake most weeks, knead a loaf now and then, or simply want the handled bowl and the finish you chose. It is TechGearLab's top-scoring stand mixer, it kneaded two minutes faster with a better rise, and the everyday conveniences are the ones you will notice.
Skip both if stiff or doubled bread dough is a weekly routine. Neither tilt-head has a direct-drive steel-gear transmission, and the Classic's speed-2 limit for yeast dough is a tell. The KitchenAid 7 Quart Bowl-Lift brings 500 W, all-metal gears, a 7-quart bowl on a bowl-lift frame and a spiral hook, and America's Test Kitchen ran 12 consecutive dough batches through it. It is taller, heavier and slower to whip small amounts, and that is the trade a bread baker should make.