(NOLOCK) vs. SET TRANSACTION ISOLATION LEVEL

As the title says, is there any difference between these 2 when it comes to procedures and/or SQL statements?

From what i have read and experienced, at a procedural level both of these are the same. But i would always prefer NOLOCK hint as i have gotten used to it so much that i always think something is not right with the code.

In SQL statements it has to do with caching (no personal experience here), read it from an online forum. Its better to use NOLOCK when running SQL statements.