I've heard he is supposed to be very good on D, but it is something very hard to quantify.
His MLB sample sizes are not all that large. He has never started more than 70 games as a catcher in a MLB setting.
One major area of concern, to me, is how he relates with the staff, and what his abilities are at bringing out the best from pitchers on the staff, especially those he catches the most.
Since Wong and Alfaro are also new to the staff, it may be hard to evaluate this area, until an adjustment period is reached and sample sizes are large enough to meaningfully evaluate.