I picked this up in a 3-pack at Ross (or TJ Maxx... they're next door!) with the Calcium Builder and Base Coat-Top Coat. I really like the hardener and would definitely purchase again. Some people online seem to say that Sally Hard as Nails is still a better choice, but honestly I usually am doing multiple coats of color on top of things like my hardener, and the dry time on this is a boon in that aspect.
The brush always seems easy to work with. I like it on top of the calcium builder because I have very weak nails, but the hardener alone is what I tried the first few times and it is a noticeable improvement when added to a routine of base coat, 1-3 coats of color with wrapped tips, and various top coats. I would definitely buy this again, especially at the price.
I love this product. I bought it at the Dollar Store in August, and I still use it regularly. If I'm not wearing nail polish, I just use it as a hardener to make my nails not so brittle, and weak.
The way I see it, it's good for a base coat, and as a strengthener; so it does it's job pretty well.
Amazing basecoat. I used to use SH Nail Quencher but have been on the search for another since it was discontinued. This stuff makes polish wear like iron and is only a dollar. Who could ask for more?