I wouldn't say 'big yields' so much as efficient yields. 6000 watts over E&F tables will out yield a 2000 watt vertical system that took as long and cost as much as to make (and uses as many plants). The whole theory with vertical is that a bigger canopy is better than a reflector - you still loose some light to the top and bottom though.
Thing is, %20 better light usage doesn't matter if your needing to run a 1/2 hp chiller, or a bunch of AC's, or your plants get pests that you can't deal with because you can't get to them.
Guess my point is that, before anyone goes vertical, they need to realize it isn't 'better', it's just different. It's pretty disappointing to put together a super-elaborate system, just to realize that (except in the winter), it's no better than normal ebb and flow tables.
Heat is much less an issue with vertical grows if done properly. You do not need an elaborate system to get large yields growing vertically. Just grow some large plants in large pots an hang bulbs around them. No CO2. Assuming you know your plants and they are not super low yielding varieties you should hit 1gpw your first go at it, if not more.
1gpw = standard for vertical. 0.6 or so gpw = standard for horizontal. 2.5ish GPW = dialed in productive hydro colloseum vertical. 1.2ish in a dialed in horizontal with all the bells and whistles with appropriate genetics etc(I have heard of the 1.5 range but those guys would probably be hitting 3gpw vertically and I am quite sure that Heath got damn close to that marker in one of his aeroponic colloseum grows but it was lost with overgrow).
At least from what I have seen. I realize a lot of guys are closer to the 1gpw mark horizontally, but they would do much better vertically with equally dialed in plants in an appropriate setup. You can of course do things wrong or poorly. Although IMO this particular technique is hard to screw up if you are simply judging the outcome based on what most people end up yielding.
You also do not need to buy reflectors.
One way is clearly superior to the other, however I totally understand that some people do not have space to do a vertical. Vertical grows require a bit more space to maximize if you are using HPS lights. You can get away with wasting more light in a smaller area growing horizontally if your space is really limited. I cannot see any other logical reason to do a classic horizontal style grow however.
But, to each their own. If you are happy with what you are doing, more power to you.