When I encounter the level of skill we have seen, I look for a couple different things to help me choose.. it was HARD this year.
For the single ship, I needed to be wowed by both conversion talent and paint job. By strictest definition, I rank any recognizable 40k bit poorly. An excellent example of this is tau fleet 2. Do not get me wrong, it was a gorgeous job! However, I could identify every bit used, and in the entire fleet, he only had 2 legit bfg minis. If he had all of his ships legit bfg, he would of had my vote hands down.
It was so hard to pick between the gorgeous eldar battleship and the jogamandir hiveship. Both were amazing conversions with stunning paint jobs... easily equal in all of my required feilds... so I had to do the horrible thing and actually vote on wyswyg. Eldar ships do not have port or starboard weapons... it makes me feel horrible but at that level I had to pick something to break the tie..