Eye-candy:
A 3-way tie between Snooze, Purplejazz and P4ul. They can all make real impressive eye-candy. I think Snooze is the swiftest and most imaginative, while P4ul spams eye-candy everywhere to the point where gameplay suffers from it, but in turn his levels look quite awesome.

Theme:
I know there are potential equals, but from what I've seen, I can quite easily determine that Snooze can create lasting, well upheld themes for his levels that hardly any other level maker can hold a candle at.

Gameplay:
For a long time now, I've considered Stripe and FS the only true masters of this department, mostly because they seem to care that much more about gameplay than eye-candy and their levels turn out to be the most enjoyable to play. I do have to point out that the likes of CelL, BloodBunny, EvilMike and Blur don't fall far behind.

Placement:
I consider this something impossible to determine.

Fastest improver:
Purplejazz went from zero to hero in the blink of an eye, while others who were new to level-making (in the community) around the same time are still struggling to produce even mediocre levels.