Hi - I've provided feedback for everyone. My approach has been to make suggestions about what particular aspects I think would make it better.
I'm big on the CRAP philosophy of design.
C -> Consistency
R -> Repetition
A -> Alignment
P -> Proximity
A little more detail here:
C.R.A.P Design - Cre8asite Forums
Google "crap design" to find more.
Quite often a few CRAP changes, and the logos submitted will look much better.
Overdoing drop shadows, fading, or having too much going on will be big negatives.
Jagged edges, or lack of crispness is a big no-no. If you're using Photoshop instead of a vector based software, you should design the logo at a higher resolution and try reducing it to the final dimensions to get a higher quality output.
In general, 2 to 4 colors is best. There have been some good entries with more color, but I lean towards reduced colors in a quality logo suitable for multiple purposes from Web to print.