One case is not necessarily better than the other it just depends on your needs and the style that you like. It should be noted there is a new type of case style on the market called ATX, it can be desktop or tower. ATX is an Intel style case that is designed to handle special ATX motherboards with specially placed external ports. ATX case and motherboard styles aren't quite as popular as the standard styles, so it may be best to avoid these unless by the time you read this they have come into style and are more widely available. Good for people looking to expand their computer systems to the maximum capability.
Cases come in small footprint, baby, standard or large sizes.
Some name brand computer companies are notorious for making proprietary cases that are small and require proprietary motherboards and other hardware for expanding it, and may also limit the number of internal motherboard expansion slots available. If the case seems small make sure that the computer has 8 expansion slots and ask if the case accepts a standard motherboard. Both questions should be answered with yes if not look elsewhere. Also ask if it requires any special mounting hardware to add new drives if you wanted to. If the answer to that is yes, again look for another system.