Cordless drills are more convenient but, are more expensive and heavier with less performance.
The 18-volt DeWalt DW995K has about as much oomph as a corded drill. But its weight requires a pretty strong user. The top 14.4-volt drills are a good middle ground between 12v and 18v. DeWalt is rated best in every voltage except 12v, where it was second to Makita.