I can only comment safely on products that I have tested myself, in addition, some things work differently on different people.
But when it comes to products that concern sensitive areas such as. the eyes, then you have to be really careful !!
I just read on DennisM's blog that he knew a girl who got it swollen eyes that she could barely see in two days, after using Xlash.
I have also heard people who have started flaking a bit, and even lost lashes when using Neulash. And my sister got red eyes in the beginning when she used Revitalash, but felt nothing of Neulash.
What I'm trying to say is - Rather spend a little more money on a good product, and reduce the risks of a reaction, and from what I understand also the level of the reaction! A little red-eyed or barely able to see, it goes without saying.
My eyes before and after.
And the lashes still stand, although I have almost stopped using Revitalash!
In addition, Revitalash is developed by one Doctor, who wanted to help cancer patients regain their hair growth. Which to my ears sounds like a more thoughtful product, which should be safer to use.
You get what you pay for!