For example as of today RedShift can hold a maximum of 256 terrabytes of compressed data while Facebook's Hadoop cluster was over 200 Petabytes in late 2012. RedShift only supports limited query and data types and a single index while Hadoop can theoretically handle arbitrary data processing. But if these constraints are acceptable then RedShift will likely be orders of magnitude faster in most cases.
Other projects/products will have different tradeoffs but they are almost always faster as this was almost always the primary goal.