I can only speak about the Spectre unit because that's what I have, and have not had experience with the others you mentioned. But, I choose the Spectre based on some simple research.
It's not really a "cold" air intake, I consider it a "smooth" air intake.
Nearly all the units out there provide this smoothing effect.
Nearly all the units use a high quality filter.
Nearly all the units use some type of guard or seperator around the filter.
Nearly all the units out there are going to suffer from some type of heat-soak.
After looking at all of this, I felt the Spectre unit would provide me with a quality product and all of the features that the others provide (I compared K&N and AEM for my 96') but was nearly half the cost.
I've had mine installed almost a week and so far so good. Install was simple, and instructions were very clear.
I know this doesn't answer your post for comparisons in performance, but could help you finalize a decision. Performance for me has been good. Check out my post on this here:
http://www.tahoeyukonforum.com/forum/showthread.php?t=15897
MWNT