Code

Optional, in form events.

All code. Powerful but sensitive to errors.

Speed

Relatively slower.

Relatively faster.

Debugging

Relatively hard to debug.

Relatively easy to debug.

Best Applications

Best at displaying large quantities of data, and creating a very rich visual impact.

Best at all the 'small' user interface messages, picklists, routine messages, etc.

Tables and Sets

Forms are bound to underlying tables or sets.

Xdialogs are not bound to underlying tables or sets.

User Control

Many built-in features for controlling user behavior.

All events must be coded, so unplanned user behavior cannot happen.

Distribution

Distributed with the table's data dictionary.

Can be bundled in a compiled .AEX library.