solo89 wrote:

In a few weeks I'll take my check ride in an ASK21. All of my training
to date has been in a G103.

The examiner told me the ASK is a lot like the Grob just better.

any advice?

we use both for basic training, and they are comparable. The ASK21 is even
better in rudder/aileron harmony. When it comes to performance, the Grob
may have one or two points, but this is not relevant for the check flight.
Did you train on a a Twin I (Twin Astir) or a Twin III ? The Twin I is a
taildragger, the Twin II/III has a nose wheel, as the ASK21, so the landing
characteristic is the same. You will have no problems.
Eggert