If you need a cheapish dress fast, David's is the place. You can try on dozens of dresses in YOUR size (2 -24 or so) and pick the one you like best. TONS of selection.
That's the good. The bad. The prices are actually not THAT great, especially when compared to the quality. The fabric just seems...cheap. My bridesmaids' dresses LITERALLY fell apart at my wedding reception (several girls threw them away b/c they had shredded at the seams or zippers had broken). The salespeople are VERY high pressure and VERY controlling. Apparently the return policy is awful, though I didn't try since I didn't buy my dress there. The prices list for alterations shows high prices on those.
They are fine, they're Wal-Mart.