I have both the 16M and the 32M
version of this antenna.
It is a voltage fed end fed antenna using a high quality 9:1 "unun" to provide a reasonably broad band match across the HF spectrum. It tunes easily with any internal tuner. Because it is fed at the high impedance/voltage point of voltage/current distribution on the wire there are less ground currents that flow (at the feed point) and therefore the radial/counterpoise/ground requirement is much less. In most cases the radio's ground will do. A good common mode choke is recommended. I spoke with CT1FFU and he said the wire lengths were arrived at after much testing and that these lengths present the most consistent impedances in the HF bands with the 9:1 windings he uses.
Don't believe the End Fed antenna works without a "counterpoise"? Check the E-Ham reviews of the Par End Fedz antennas. I have several of these too, they work amazingly well.
I have the 32M version of the EZ-Wire installed as an inverted "L" at about 60 feet in my small yard with 1 tree. I attached tuned radials and counterpoises just to check, they made no difference at all.
I also had a 133' "New Carolina Windom" installed at 36' at the same time as the newly installed 32M EZ-Wire so I was able to do some direct comparisons:
On 20M- 6M the EZ-Wire is better 90% of the time, some times as much as 3-5 S-units stronger.
On 30M the EZ-Wire is better 75% of the time, again with as much as 3-5 S-units.
On 40M the EZ-Wire is better 60% of the time, often by a few S-units.
On 80M the Windom begans to win out more often, but not by much, and not enough to disappoint me.
On 160M the Windom is usually stronger on RX but the Windom will not load on 160M, the EZ-Wire will easily load on 160M and has given my some of my first 160M contacts so it wins for me there.