What makes a bulb perform better? Well size and quality. You want to look for bulbs that are firm and have no sign of spots, softness, or look diseased.
Also, size has a lot to do with it. Buy them big. Bigger is better, and the old saying is true, "You get what you pay for."
The biggest bulbs will produce the biggest flowers, and they'll generally be priced a little higher than the smaller ones. If you want the best flowers, buy the biggest bulbs you can afford.
Also, when dealing with tulip bulbs, don't be bothered if the "tunic" (the papery skin covering the bulb) is torn.
A tulip can be very healthy and will grow just as well without its tunic. Actually, some research shows that removing the tunic may encourage rooting after the bulb has been planted.
Tulip bulbs should always be bought large because they produce their biggest flowers only in the first year.
Bulbs Not To Buy:
Never buy any bulbs that are soft, mushy, or spotted with disease. (See illustration)
A Note About Daffodils
Although big bulbs give the largest flowers, sometimes you can buy the smaller bulbs in bulk, especially if they are daffodils.
Daffodil bulbs multiply and grow larger every year, so if you can wait a year or two. but the smaller bulbs because they will grow.
Plus the smaller bulbs don't mean they aren't any good, it just means that they are young. Buying daffodils in bulk is good because then you can have enough to naturalize them in a large area.