The top right and the bottom left are my two favorites, so I agree with all the comments
I like the top right for his posture, and as Thesilentone mentioned, for the good background and lighting. It's a good stack and a good picture. He's in great shape here, and sure he looks like a bitch/an immature male, but I won't get too picky LOL
I like the bottom left because (like the top right) I find it very aesthetically pleasing. I think it shows his structure and conformation well, and he looks like a male here. I had brushed him the night before, so the insanely wavy patch of fur above the withers is relatively tame. His topline probably looks the best here.
I actually like that most people will look at the bottom left picture and realize he has a fair amount of rear. Gives me a chance to remind them that "angulation" is not a four letter word
What I don't like about the bottom left picture is the overgrown grass, and all the dead grass strewn across the field. I'd PS it out, but have no patience for it LOL He also seems to be posting just the tiniest smidgen? Also not happy with his muscle tone and weight, but it's nothing that stands out.
And yes, I agree that the lighting in the top left sucks (bright summer afternoon) and the harness in the bottom right is distracting (I was showing off the new harness in that picture).
These were all taken within under a year of each other, between ages 3 and 4. I don't think he would have noticeably filled out during that time. He does appear to lose substance in the top right picture, but he was very tense and upright there. I think he tried to stand on his toes!