It looks to capture the 121 uniqueness shape and detail wise which should be what sets the standard for a model. It's a given that all locos should have sound mechanics and run great straight from the box in this day and age. Although a small few rogues will always escape from the factory.
Any of the three MM Illinois built locos I have are spot on in every department and no doubt these will be the same.
As Fran has said the design work gone into this model is of the highest standard.
If the area between the grilles remains see through on the sides it will be epic. I always wondered would it be possible to remove some of the chassis block on a 141-181 to achieve that effect.
Can't wait for 124 and 134 they are going to be special.