People sometimes complain that the same blend may be a bit different between bulk and tinned, but I believe for the most part they are the same stuff.
Certain high end blends are only available in tins, so that may be where the "higher quality" part of the question comes in.
For the most part, I factor in how much it will cost me to buy mason jars to store the bulk tobacco in, then look at the cost to buy the same tobacco already tinned. If theres not a major difference in price, I have started going with tins just because its less work, and will age perfectly in tins. Not to mention be a lot lighter and less bulky than jars.