Very nice! Anyone who has tried to pose an animal like this can appreciate how perfect this pose is.
I would agree that the lighting on the head is a bit hot, but I have no problem at all with the composition here. The lighting seems perfect on the rest of the pup to show off that silky hair, and I like seeing the chest of the animal.
I have an online pal who does dog stock photography, and she says the show dogs are generally easiest to pose because they've been trained to Sit & Stay - so again, if this was a more casual attempt, it's well done. Nice work!