Okay since I have used both I will post my experoientace.
Hennalucent Neutral is the one I tried. It has other ingredients including protien and others.
Henna, Hydroxyethylcellulose, Sucrose, Quaternium-19, Hydrolyzed Animal Protein, Guar Hydroxypropyl Trimonium Chloride, Citric Acid, Glyceryl Stearate SE, Sodium Lauryl Sulfate, Stearalkonium Chloride, Fragrance, Plant Extracts and other ingredients.
The neutral is an off white color, which throws me off because even cassia has a darker color than that. Anyway, I tried it and it is sorta conditioning. I give it a 2/5 when compared to the "real" henna. I mixed it with plain yogurt. it is not as cooling and soothing to my scalp as henna is. It actually tingled a little.
Henna, on the other hand is powdered form of the leaves from the lawsonia inermis - and that's it. No other ingredients. "neutral henna" as it is often called are normally from the cassia obovata plant, but I have also seen the rhazya stricta, cassia auriculata and one other plant that I cannot remember. Those are not henna at all, but people just call it neutral henna because they condition w/o the color that henna has.
I personally have used henna, cassia obovata and rhazya stricta. They are far better than hennalucent, in my honest opinion. But, I think hennalucent is a good option to try and use because it is not a bad product. I just don't think it really represents the real henna.