Ha! If all the conditions are right, they both do!! Personally, I think it depends on your philosophy towards keeping plants. Go to Dennerle's wed page and have a look at the Dennerle 'style'
http://www.dennerle.de/. Nice tanks, but if you read the literature, the examples they show are quite long-standing set-ups, not set-up, and ripped down after a year or so (seem to remember one in their guide which has been going for some 8 yrs). The approach does not really 'overdrive' the tank with respect to nutrients and light in the same way that a lot of folks here are apparently doing. Lay-outs are often more wild looking with quite a diversity of plants, i.e. aquascaped in a quite different way.
Put simply, the Dennerle approach strictly speaking involves dosing Fe (E15) supplement and general fert (V30) alternately on the 15th and 30th days of a cycle, and performing a water change once every 2 weeks. Only quite recently has a daily dose of supplement (A1) been added to the range. Traces and vitamins (S7 & PG7) are also meant to be dosed once a week. Both Dupla and Dennerle use heating cables, and substrate systems are quite different to things like flourite and eco. My experience is that these kind of tanks are not quite on the knife-edge when it comes to nutrients, light etc compared to some of the tanks we see described here. I'm currently on a bit of a roller coaster with a new high light, high nutrient (for me anyway) tank which I set-up 10 days ago. The approach is different to my dennerle set-up and the end result will be somewhat different, and I think that is the point. One is not really better than the other, just different! Which, of course isn't much help to you..On a final note, my Dennerle system pretty much runs itself, although now I just use TMG a couple of times a week as a fert, so I guess on the whole maintaining the system isn't quite so involved. Just my experience.
Regards,
Nick