I have the D4 and the Incra fench system, and use both, depending on
the job. For what you say you're going to use it for, I recommend the
The Incra is more versatile, but has some drawbacks - the joints are
slightly hollow, for example, and the setup is picky wrt centering the
boards. The D4, however, makes fully solid joints, which are a bit
stronger, and the setup is a little more robust, especially if you're
doing more than one item in a batch (i.e. six drawers at a time).
OTOH, if you tend to work with smaller items (like, 1/4" stock), the
Incra is more usable in the small scale, easily supporting down to
1/8" thick stock. I use the Incra for smaller items where strength is
less critical (like small boxes or serving trays), and the D4 for
larger items or items needing more strength (like drawers).