Recommend gitlab-experiment framework

doc/development/experiment_guide/experimentation.md

@@ -6,6 +6,9 @@ info: To determine the technical writer assigned to the Stage/Group associated w
 
 # Create an A/B test with `Experimentation Module`
 
+NOTE:
+We recommend using [GLEX](gitlab_experiment.md) for new experiments.
+
 ## Implement the experiment
 
 1. Add the experiment to the `Gitlab::Experimentation::EXPERIMENTS` hash in

doc/development/experiment_guide/index.md

@@ -46,16 +46,10 @@ One is built into GitLab directly and has been around for a while (this is calle
 to as `Gitlab::Experiment` -- GLEX for short.
 
 Both approaches use [experiment](../feature_flags/index.md#experiment-type)
-feature flags, and there is currently no strong suggestion to use one over the other.
+feature flags. We recommend using GLEX rather than `Experimentation Module` for new experiments.
 
-| Feature              | `Experimentation Module` | GLEX |
-| -------------------- |------------------------- | ---- |
-| Record user grouping | Yes                      | No   |
-| Uses feature flags   | Yes                      | Yes  |
-| Multivariate (A/B/n) | No                       | Yes  |
-
-- [Implementing an A/B experiment using `Experimentation Module`](experimentation.md)
 - [Implementing an A/B/n experiment using GLEX](gitlab_experiment.md)
+- [Implementing an A/B experiment using `Experimentation Module`](experimentation.md)
 
 Historical Context: `Experimentation Module` was built iteratively with the needs that
 appeared while implementing Growth sub-department experiments, while GLEX was built