I'd be a bit afraid to bring up this one. I posted on this topic before, and someone incorrectly guessed that I was suggesting that a nice photo of a kid with his plane shouldn't have gotten Photo of the Month, when I never suggested it at all. Actually that was a great way to promote model building.
What I had said before, is that they obviously look at the aesthetics of the photo, versus the quality of the model. Put a great background in with great lighting and colors, and you can get it. A masterful build that perfectly matches the box art, which BTW is what Guillows is suggesting as a potential result to enhance their sales, will likely not get POTM. While I do believe that there should be some diversity in the selection criteria of the models, the quality of the build should generally be high on the list. That said, I would expect to see your models as POTM often David. Sometimes I wonder if the criteria is simply random selection, such as when all the photos of a particular month were taken indoors and there clearly appears to be more attractive builds with better photo quality that are not the winner. One thing's for sure though David: They'll never get two nicer Edge 540s submitted in one month.
I never got POTM, but my SE5A was at one time the photo shown in the parts listing page for the model. I never thought it was a great photo, but given what I know about outdoor background influencing photo choices, I believe I know why it was selected.