If you want to see a side by side comparison of the ERA heavy duty fan vs the standard fan, look here:
http://www.chuckbrandt.com/living.htm
I guess I'll be ordering one too. I've never had overheating problems before but the 100+ degree weather combined with stop and go cruising (mostly stop) at Hot August Nights this year was too much for my ERA. While temperatures that extreme while sitting in stop and go traffic is rare for me, it's also a pain when it happens.
Chris