Cute, but economically, how does it compare to a nuclear power plant that runs 24/24 for decades and use very little land?

This can be significant. It's unobtrusive design makes it an ideal method for producing energy that can supplement solar for private homes as well as large scale applications. Especially since it can be used no matter the time of day or night, as long as there is wind.
No dead birds, unsightly vanes, minimal noise, and far less maintenance and installation costs. It also makes it possible to have installations closer to the end-user so that transmission loss is negligible.
If Vortex can design a proven reliability, the sky's the limit!

what concerns me is the oscillation. Even if it has no moving parts , i think it will have more failure rate than a normal wind turbine

Hmm will they not get to a harmonic frequency that will cause them to create a nice note

The energy contained in moving air is proportional (among other things) to the air mass, which in a wind turbine setting is proportional to the capture cross-section. A small cross section means low power.

Though obviously not as efficient as a "HIGH-SPEED", directly wind-driven turbine,
There is no such thing. Here I am assuming that you refer to RPM and not the actual speed of the tip of the blades. I would reAlly appreciate seeing some actual figures here.
What people should also take a look at is the Pearl River project in China using vertical turbines which are absolutely safe for the birds.

Agree that the article is a bit short on specifics. And what about metal fatigue if it's flexing.
I had to laugh at Freyr's comment, though as I live in Southern CA and we just experienced exactly how reliable those nuclear plants are with the fail of San Onofre power plant. Nuclear fans never seem to include cleanup costs in their calculations. Although, even if they did, they might be better than coal.

4kW from a 41' tall pole ... you gotta be pulling my leg. Show us the test data !!!! And what happens in a storm ?

To Freyr Gunnar well when you consider the clean up and storage cost for your traditional nuke plant this is a good option now if you used a Thorium reactor wind and solar combined don't hold a candle to it.

It looks to me to be a very feeble device, and seems hardly capable of giving out much electricity. No performance figures seem to be available.
By the way, what a lovely photograph of Chem-trails. Don't know what they are? Check it out.