Quote (Sonor @ Oct 14 2015 01:35am)
BB allows for your stronger side to compensate for your weaker side, where as DBs isolate the specific arm/side.
Often times it comes down to preferance, as if you're following a balanced regiment the difference between the two is fairly insignfiicant.
In regards to your comment about sticking with the same exercise, it's called muscle confusion.
Any time you perform an action over and over, you'll get better and better at it. This can be seen by drummers practicing rudiments, guitarists practicing chords, etc: The more you do something, the more proficient you become at it.
Unfortunately, when it comes to bodybuilding, allowing your body to get used to the movement of a BB or DB bench press can be detrimental.
To surpass plateaus and ensure muscle confusion, you HAVE to change your regiment and implement different exercises. Although your chest routine may be working for you now, allowing you to add 5lbs every week, over time you will find that 5lb addition is only possible if you implement a different routine.
TL;DR - Personal Preference, change of routine, etc.
That's utter shit