I believe the front loading ones use less water (but you can check the manual for that info). Front loaders are also supposed to be kinder (easier) on your clothes because there is no agitator pulling and stretching on them like the top loaders.

Front loaders generally are smaller so you may have to do more loads (which negates the economy on water noted above)but if you're just 1 or 2 people in the family, it might be ok.