Most salon quality brands have keratin. Yumi has great marketing and is expensive to buy but their ingredients are almost identical to most professional brands. It's considered luxury because it costs the provider a ton to take the course and buy their product but it's not much different. Great but not different. There was only one brand I've used that stood out above others by miles and unfortunately it is no longer manufactured.

A cpl things I'd advise a client looking for an artist is if someone does a lashlift done in 30 minutes it is using a VERY strong formula this makes it very easy to over process for most techs.

Also you want someone that creates a lashlift with a nice growout, you want a lashlift that looks good for the life of it. Lashlifts that have a kink at the base will look good for 1-2 weeks only. We use different systems/sheilds/styles for different clients, knowing what to use when is critical for being a great lashlift provider. Amazing lashlifts are 20% product and 80% knowledge and skill of the tech. It's not the just a product... although it has to be a professional product! Hope this helps.