"J. Clarke" writes:
Only if the user screws up, like its competitor.

Assuming we're talking about the Incra, which is the only dovetail jig
I know about that requires eyeballing a center...

By design, you can't make solid half-blind dovetails with the Incra.
There will always be more wood removed than needed, because the jig
just can't make exactly the right cuts, so there are always small air
pockets hidden within the joint (even if there are no visible gaps).

The Incra can make nice round-bottomed pin sockets for half-blind
dovetails. However, to make the tails, it uses two cuts perpendicular
to each other - resulting in a square "peg". The socket is deeper
than the peg, so the pieces fit together, but there's an air pocket
where the square peg and round socket meet.

In the case of through-dovetails, the Incra can't make the spaces
between the pins properly. It actually cuts *tails* first, then
removes most of the extra wood using a dovetail bit with the wood flat
to the table. Even then you have to hand-carve some remaining wood.
But the initial tail cut leaves an air gap when you assemble the
pieces.