There is a difference. A higher impedance will also increase damping factor. This will mean more control over the cones, effectively making the amp/cab system sound tighter. There are a lot of variables in the equation when we are talking about multi driver cabinets, though. In most cases, 4 (or more) driver cabs have a combination of series (which results in a higher effective impedance load) and parallel (which results in a lower effective impedance load) connections in order to arrive at the final impedance that is desired. The parallel connection allows for superior damping. SO, if you wanted the absolute tightest possible sound from commonly available guitar speakers, a 16 ohm driver in a single driver cab would be best case scenario. There are ALWAYS trade offs, though. I won't bore you with the finer details of how proximity effect causes certain frequencies to be boosted in multi driver systems, thereby making 2 or 4 driver cabs have more apparent low frequency response. There is no simple answer if you are trying to figure out the "best" way...