Doberman pet portrait

One of my Christmas commissions, due to be started tomorrow is of a beautiful Doberman. I really like Dobermans and it's always nice to draw dog breeds that I personally like. The customer was unsure about whether to have it in graphite or pencil, and to be honest I was a bit unsure what would look best. On one hand black dogs often look better in graphite, but, being a Doberman he also has tan patches and coloured pencil would pick up the differences in colour where I think with graphite it would be hard to differentiate between the black highlights and the tan fur. I put the query on the pet portraits forum i'm a member of and one of my fellow artists suggested drawing a sample in both graphite and colour to make it easier to compare. So I did! I think he will look better in colour, but I have emailed the customer with a copy of the picture and my suggestion and I will wait and hear what she says. Here is the samples - what do you think?