Apexi S-AFC or HKS S-AFR?

so, which one is better?

I really was interested in the HKS unit. similar price and would probably work good. here's some info I had saved from a long time ago. enjoy

-HKS AFR (Air Fuel Ratio Regulator)
The AFR is designed for lightly tuned vehicles (intake, exhaust) to allow for mild adjustments in the a/f mixtures through sensors. The AFR allows up to 1 A/R point; rich or lean, for the best possible power gains.

HKS AFR is a simple fuel adjusting device that adjusts the Air/Fuel ratio by changing the airflow voltage output to the vehicles factory stock computer. The AFR was designed for vehicles that are lightly tuned (air filter, exhaust system, etc.) and that need only slight fuel adjustment. The 10 setting adjustment indicator allows the user to richen or lean the stock settings by approximately 0.2 of an A/R point. Both the lean side and rich side have five notches. This enables the user to search for the best possible set up for your vehicle! The D-Type and L-Type are the two types of AFR available.

hope this helps.

WRC, that for the regular AFRs. Here's what HKS says about the Super AFR:

The HKS Super AFR is the very first airflow meter correctional device in the industry with a built in CPU. The advantage of having a built in CPU is that instead of making corrections to the airflow meter voltage/map sensor, the characteristics of the airflow meter/map sensor is inputted in the CPU so it can calculate the most accurate amount of air flow. Since the correction will be made to this specific intake volume, the correction ratio of fuel will be precise and proportionally correct. With an illuminated digital display and face mounted adjustment controls, the compact Super AFR is a simple to use fuel computer that offers many of the advanced features that were once exclusive to full engine management systems. The L.E.D screen is utilized to digitally display all adjustments as they are entered along with RPM and fuel % adjustment (over baseline) in real time. The Super AFR is compatible with virtually any fuel-injected vehicle, 12Volt, 2-12 cylinder vehicle that utilizes a hot wire, Karmen Vortex, airflow meter or pressure sensor. The internal CPU allows it to be versatile and utilized on many of the newer type airflow meters.

The air/fuel Ratio Correction function of Super AFR allows complete fuel curve tuning by offering eleven points between 650 and 8000 RPM of adjustment, that can be arbitrarily moved in 50 RPM increments. Each point of adjustment offers a tuning range of 50% rich to 50% lean of the factory baseline setting in 1% increments. Also incorporated in the Super AFR is the Idle Correction function, where Idle fuel mixture can be adjusted from 50% rich to 50% lean of the factory baseline setting in 1% increments within the idle range of 650-1500 RPM. This offers the ability to adjust idle air/fuel ratios as modification progress and require further specific levels of tuning to compensate for the characteristics of high lift cams and/or larger injectors. The response function, similar to the one in the VPC, allows for adjustments to the fuel settings upon throttle inputs to improve driveability and performance. Much like the corrections made to the idle mixture to compensate for high-lift cams and/or larger injections, the response function can also compensate for differences in fuel requirements upon initial throttle input as airflow characteristics are changed from high-lift cams, larger injectors, and bigger turbos. In detail, the response function allows for management of engine response in milliseconds with six points of air meter signal adjustment between 650 and 5000 RPM that can be randomly moved in 50-RPM increments. Additionally, an Electronic Idle Stabilizer function (EIDS) function, which buffers the dramatic airflow meter signal fluctuations, prevents the engine stalling or stumbling effect associated with the sudden imbalances in the air/fuel ratio of airflow meter-equipped vehicles that utilize discharge blow-off valves that vent to the atmosphere.

It sounds good, but I wonder about this and ECU learning. It has been said that the ECU (2000+) will learn and override the corrections that the S-AFC except at WOT. If the S-AFR is constantly adjusting (learning the ECU?) and the ECU is learning the S-AFR, which will win?