I've run Q-Jets, AFBs, Edelbrocks, Holleys, Webers and both BG Speed Demon and Mighty Demon carbs and I can tell you this for sure; "out-of-the-box" means nothing more than the carb was, at some point, in a box. Each one needs to be taken apart, cleaned and inspected and re-assembled and tuned to run on your engine.
If you get a Holley that ran better than an Edelbrock (same size and vice-versa) it's very likely that it was nothing more than the stock jet configuration fit your particular application better than the other one and that was more-likely due to market studies of who's buying their products to install on what engine than anything else. The point is, each carb needs to be set up to run with your exact combo and preferences. They each have their own upsides and downsides depending on what you're used to.
For the record, I'm a huge BG fan, even with the problems caused by Barry and his crew themselves. He appeared to be a little "messed up" by stress, perhaps. Their quality control sucked and their customer service was even worse. Having said that, he had some really innovative ideas and all of the old baggage is supposedly completely removed from the new owners and operations. I hope so and am looking forward to seeing what they come up with.
I also believe Holley has been in bankruptcy multiple times. I can't tell you squat on which one does best off-road though
To the OP: Edelbrocks can be set up pretty darn well with their tuning kits but it's trial and error without a good grasp on what you're seeing/feeling and and a/f monitor. Tuning the secondaries is a b*tch because you have to either add or remove weight from the counter weight on the air valve.
Holleys, on the other hand, can tune the secondaries, accelerator pump and main jets with relative ease but the transition circuit and air bleeds must be modified by drilling to correct anything.
Go custom and avoid all of that crap