From MySQL 5, Stored Procedures are now part of the MySQL database engine.

> Stored procedures would mean less coding on the Perl side.

Keep in mind though, that on this moment this is the only advantage you have.
The implementation of sp will lead to worse performance than the embedded SQL because there is no query execution plan caching implemented yet, meaning the stored procedure must be re-evaluated each time it is executed (perhaps this is changed in a later version).
On this moment, the main advantage you get are code encapsolation and putting the business logic into the database tier.

When you want 'raw speed' use the emmeded way, and read Speeding up the DBI for optimal performance