I'm looking to install an app that uses preloaded maps rather than ones that are downloaded as you go.

What are my options, and which is considered the best?

Thanks

Preloaded maps? By that you mean not depending on Internet?

The options are several:

iGO (Motonav)

Navigon

Ndrive

Sygic

PPG

....


Take a look around the section. You will find them.

And the best? Depends on personal likings and availability and quality of the maps.