If the airflow around the heat exchanger fails (fume hood stops working) this would be much less efficient and potentially much more of a hazard for escaping, flamable, gas and no extration to remove it.
Having worked with aircooling in small to medium sized industrial processes (i.e. up to reactors of 700 L capacity), and hence a bit familiar with the physics involved, too, I'm not as sceptical about reliability here as you are - esp. not if you treated the cooler like any traditional one, i.e. would regulate reflux to only make use of the lower 10-20% of the internal heat exchange surface.
the thing that just stops me from trying for this however is the price : US-$ ~ 350 is quite hefty in my opinion
... and I don't reflux that much anymore these days in my field anyway, so the amortisation calculations given at respective websites don't count for me
anyway, getting one of these from eBay at let's say 20 bucks, I'd give it a try...