Out of the box, Edelbrock carbs are more forgiving, but Holley's are much more fine-tuneable. I eat, drink, and schit Holley's. I can rebuild them in my sleep. In my opinion, Holley's are leaps and bounds better than Edelbrock's, but it depends on the user. If the user is clueless about Holley's, but
thinks they know what they're doing, horror stories are usually the end result. BUT, if you know what you're doing, they're the best, IMHO.
Take care,
~Chris