First, it is ok to choose generic brands, oftentimes these brands are just as good as the ones with fancy advertising.
Also, there is a slight different in the multivitamins for men and women. Women's vitamins often contain iron, which is a necessary supplement, whereas men need little or no iron.
Lastly, test your vitamins by placing one in a glass of water. It should dissolve in under a half hour. Some vitamins can take up to two hours to dissolve and are therefore useless, as they won't absorb into the bloodstream.