Evan Williams (or Evan Williams black label) is a middle shelf whiskey most people are familiar with. As a straight Kentucky bourbon, it's aged a minimum of four years and is produced at the Heaven Hill distillery in Louisville, along with a number of other recognizable brands like Heaven Hill and Elijah Craig. Although some version of "Since 1783" appears on every bottle of Evan Williams, whiskey historians (yes, that is a job) have pointed out that it has not been operating continuously that entire time, and a more accurate date might be somewhere in the early 1900s. Because of it's affordable price point and (relatively) smooth flavor, Evan Williams black label is the second best selling bourbon in the world, following only the value priced Jim Beam.
Black label:
Nose: Similar profile, but a little harsher
Taste: Similar, with a slightly sweeter and more buttery flavor, with a lighter mouth feel.
1783 Small Batch:
Nose: Clean, nutty, buttery, roasting corn, clearly a sour mash.
Taste: Again, it's obvious this is a sour mash. Oaky, with a buttery mouth feel and finish.
Recommendation: I could go either way on this one. If you want to spend a couple extra $ to try the small batch, go for it, but don't fall prey to premium pricing in stores that try to take advantage of you by capitalizing on the "small batch" on the label. You really shouldn't pay more than a buck or two more for it. I could see both of these bourbons going well in a mint julip.