[peggybac]

If there’s a mistrial, there will be another trial. The charges should be dropped. Period.

[MortMan]

Dismissal for mistrial with prejudice prevents another trial. Dropping the charges does not preclude filing new charges later - the decision to "drop" is a prosecutorial decision, as opposed to one by the court.

Clear prosecutorial malfeasance like withholding evidence (that they then try to get admitted after they and the defense have both rested) needs dismissal with prejudice.