I think both ALA and Cilantro are useful. Although I've noticed more obvious improvement with cilantro, I've definitely had improvement with ALA too. I don't think cilantro can pull mercury out of the brain (if someone out there knows better, please let me know), since ALA can, it remains a very important part of chelating.
Cilantro has more side effects than ALA. My side effects started as somewhat bad, but became milder over time. Side effects for both include fatigue, emotional issues and a temporary worsening of other symptoms. I have some difficulty concentrating, organizing my thoughts and making decisions during a round. I may have itchy, red places on my skin which go away within a day or some of my joints may turn red and hurt a little. My veins become easier to see. I often develop a stuffy nose and, sometimes, coughing while chelating. I will have a mild yeast reaction about a week after starting a round.
These symptoms are just somewhat worse with cilantro. Maybe a sign that it's pulling more mercury out? That could be a good thing if your body can handle it or a bad thing if it can't. When I take a break from using cilantro, I will feel bad the next day, but using chlorella a few more times after taking a break makes that bad feeling go away.
It also seems like cilantro leaves more mercury stuck in my skin. That makes taking a sauna very important while using it, so you can sweat that mercury out.
ALA can produce headaches or strange feelings in my head. That's also not too bad and I don't notice this much now.
The only serious trouble I've had is with slow-release ALA. This caused some pretty terrible problems which continued for a long time after I finished chelating. I began chelating with cilantro/chlorella again and those problems went away.
My Chlorella is a typical Japanese brand, so the label is written in complicated Japanese, included many difficult Chinese characters, so it's difficult for me to give you any details about the Chlorella itself. I haven't had any problems with it.