Coolglide Excel and Safety

I went to a clinic and was told that coolglide excel is the safest laser out there, has less of a scarring effect, and is better for darker skin (I am of euro descent, so I have olive skin, but not really tanned). Are these claims accurate?

Also, could someone tell me what they think of Alexandrite in terms of its safety and effectiveness. I have read a lot of posters here who think Lightsheer is the best laser. How safe is Lightsheer though? I am really worried about scarring and changes in skin pigmentation. Is skin cancer a legitimate threat from any of these lasers?

ANY guidance would be appreciated.