While I have not used this commercial LNR antenna, I can see the appeal of it. It looks like a viable system for many portable operators.
I use a very similar homebrew end-fed design, and it works just great. Key points:
1) 66 feet of #24 teflon wire
2) End-fed with homebrew, high-Z tuner with complete adjustment of complex impedance
3) Link at 52 feet for 30M or 17M
4) EFHW on 40M
5) EFFW on 20M
6) 66 feet matches on 30M using tuner and link shorted! Non-resonant but very effective!
What you say about the four-lobe pattern for the End-Fed Full Wave (EFFW) is true, except that when the 66-foot wire is set up as an inverted-L - using a large fishing pole and/or trees - the pattern is a beautiful heart-shaped cardiod shape, with a single null off the far end of the wire.
Usually I set up my wire running north, sometimes south, and I have an almost omni-directional pattern on 20M except in the direction of the far end of the wire - away from the support pole. Here in Colorado, this is almost ideal.
My RBN spots and results using this setup are just fine. I use a KX2 at 10W - it's almost overkill.
Look at my recent RBN spots up now and see.
With the 52-foot link open, the wire is close to EFHW on 30M, and EFFW on 17M - similar patterns with the inverted-L.
I prefer using a tuner so I can get perfect matches, no matter what the set-up is on the mountain - operating on solid rock, deep snow, high or low wire, far end of wire very low above tree-line, wire running through a tree, etc. Using resonant tuners has taught me how much antenna impedance may change, depending on the many variables at the site. Often I cheat and use forced matches, non-resonant combinations, usually with no counterpoise - I save time to make S2S contacts, etc. After a while you learn your tuner and its settings, and then you have real flexibility.
My tuner sits on the ground - no need to suspend it or fool with it.
Otherwise, just use an autotuner!
Opening the link is very easy using a ~6M fishing pole tied to a tree. Just lift the pole, tilt it, and the wire drops to where the link can be reached. Tilt the pole back, and get back on the air. I like to get up once in a while anyhow, so this works well. Even when I guy the pole above tree-line, it's easy to tilt it over to change a link.
Often the link can be reached with a long stick, if the wire's not too high - the pole bends, so you can just pull the link down without even tilting the pole.
I use dacron string and mini-banana connectors for my links. They are almost weightless and survive abuse and violent winds well. If something breaks you can make it work in the field.
Once of the big advantages of a resonant tuner like mine: it provides additional selectivity for the radio. When you have a couple of guys running 10W, set up only 100-200 feet apart, having tuners can make for a much happier activation when we're both on different bands at the same time. Receiver selectivity is sharper, and transmitter spurs are limited.
N0TA and I often run simultaneously on different bands using these 66-foot antennas and tuners, 200 feet apart, with almost zero interference. It helps if the wires are not broadside to each other.
Anyhow, the basic concepts of the LNR antenna are sound. Their best feature is the matching network without knobs. For many operators, average sites, and some radios, this is good enough. Just note that however you cut the wires to resonate the three different bands, there will be impedance changes depending on your site and set-up. Isn't this obvious ? Try some Eznec models to see how much Z of an EFHW can change just with height!