Okay, for the people who may be in the same decisive split as that I was, here are the differences between the Atomic Doubledeck 3.0 SL and Volkl Racetiger SL's. I have skied the Atomic's in 165cm and the Racetigers in 170. However the differences in behaviour that were due to differences in length, were minor as far as I can judge.
Observations and views
When standing still, feeling and observing the ski's, the Racetigers are a little lighter in weight and longitudinal stiffness is a little stiffer for the Atomics. Interestingly the Volkl has a clean arc when flexed and the marker bindings clearly move with the ski being flexed. The Atomic ski on the other hand has an asymmetrical flex pattern, since the tips of the ski is not doubledeck covered, it bends much easier than the parts that are covered. Also its bindings did not move that much when flexed, suggesting that the part under the foot remains flatter than the rest of the ski, when flexed. Differences in torsional stiffness was too difficult to measure by hand for me. Radius of the Atomic was quite some shorter (11.1m, vs 13.6 of the Volkl), but was wider under the foot (69mm vs 68mm).
An interesting detail in the built of the ski is the locations of the metal. The Atomics have one titanium plate, located between the internal wood and the ski base, like most skis that carry metal. On the other hand, the Volkls are described to have a double-titanium plate, of which one is visibly located on top of the ski and the other one is supposedly located between the wood and the base, thereby sandwhiching the wood core with metal. A downside of this metal top sheet is that when the skis hit each other, your edges have metal-to-metal contact, thereby dulling the edges. Upside is that the ski has a full sidewall, compared to the capped-sidewall hybrid system of the atomic. (Forget about waxing the sidewall, it is not made of p-tex anymore like it was some years ago).
Skiing experience
Skiing wise both skis have a lot in common with each other. Both skis feel very lively, mainly due to the small effort it requires to initiate a turn, and the strong rebound they both give. To summarize: both skis have to be guided and tempered, rather than pushed have put effort into them. The Atomics are known for their immense rebound, which they indeed have more than the Volkl. To my taste, especially when skiing moderately long turns, where G-forces really build up,the rebound can be somewhat overwelming. The Volkls have a similar rebound, to the Atomics, but just slightly turned down. Where the Atomic is put on "volume level 10", the Volkl is between 8 and 9.
Turns are notably shorter skied with the Atomics, which fits with their smaller radius. For both skies, short and moderate turns are very well and confidentely skied.
Stability on speed was better for the Atomic ski, but still speeds up to 90 km/h can confidently be achieved with both. After that the Volkl is more prone to generate a more unstable feeling which I cannot accurately describe. This matches the observation that the Atomic felt somewhat stiffer.
Another thing that I experienced immediately on the Atomics is that a really small knee or ankle movements initiate a turn, a little bit more than the Volkls. Contrarily, where the Atomics have easier initation, the Volkls have stronger edge grip, also on ice.
Now a skis that hold really strong grip, may have such great torsional stiffness, that it may be difficult to ski skidded turns. Here was where I found the largest difference between the skis. The Atomic ski is considerably less turn-able when skiing skidded turns, it is more "on rails", but then in a negative way. This is also much more pronounced in the new doubledeck 3.0 skis compared to the older D2 SL from 2012 that I had. This is also where the versatility of the Volkl, described in other reviews comes from, I am convinced. The Volkl has absolutely no problem with ski skidded turns. It turns on a dime, and it does with greatest ease. This makes it better skiable in moguls, crud, and slopes that are too steep to carve comfortably.
Both skis have their outside-visual gimmics ofcourse. For the Atomic, the doubledeck system is clearly visible and has proven its function and is responsible for a great part of its rebiound. I did not notice the RAMP technology that puts the skier forward up to 10 degrees, when the ski is compressed/flexed. This may be a positive thing, since also was not put back on the ski in short turns. Hence, it may have worked without disturbing me.
The UVO damper of the Volkl has been claimed to damp vibrations, although the metal appears to aluminium or magnesium (or some other lightweight alloy), that is not that heavy, which would be needed to effectively cancel out the heavy vibrations of a ski at speed. Therfore I was not yet convinced of the system when I had the skis in my hands. Whether or not the UVO works or not, the ski is remarkedly stable, in all directions.
Summary
The Non-FIS SL's of Atomic and Volkl ski are both very lively feeling skis. Structurally they are quite differently built, with both having their unique properties. The Atomic has easier turn initiation and is more stable at speed and has loads of rebound. The Volkl has somewhat more grip, somewhat less rebound but still has plenty, but is much more versatile since it can do skidded turns and handle crud-condions much easier.
You could say the Volkl has 10% "less" turn initiation and high speed stability, but trades that for 40-50% easier skidded turns and handling crud.
I am happy that I have bought the Volkls and if someone has a question regarding something I have missed in the comparison, I am happy to answer as well.
As I said, if you are serious about running gates, do yourself a favor and buy the right tool the first time, always cheaper in the end. 
