Expensive, at €20 for a 0.5floz bottle, but after using it constantly for around 9 months there is still 1/2 a bottle to go.
I used to have terribly weak, bendy, peeling and breaking nails. Not anymore, in fact my biggest problem now is the weekly filing to keep them at a length where I can still type!
Used as a base coat under colour, or on its own.
Brilliant stuff.

It didn't take too many applications of Hard Rock before my nails improved about 1,000,000%. My nails no longer peel like they once did. This product is just spectacular. Super, super impressed.

I like this product! My nails feel strong, and my manicure lasts very long when I use it as a base and top coat.

I think $20 is pretty expensive, but I've spent more on face products that don't last as long. I will buy again, but hopefully a sale will pop up :)

I just bought this today so I can't speak to its' nail-hardening abilities, but it dries very quickly and leaves a nice sheen (not overly shiny).

I'm halfway through my second bottle of Hard Rock. I rarely repurchase anything, but I LOVE this product. I use it as a base coat on my thin, peely fragile nails. Not only does it make my nails more resistant to breakage and peeling, along with keeping them from bending as much, but it keeps my polish on for a whole week. I first apply to tips, wrapping over the edge of my nail, then paint the nail itself with a thin-to-medium coat. I wait a few minutes, then apply polish and follow with Poshe topcoat. You can also use Hard Rock as a topcoat, and it works really well that way, but I prefer a fast dry product. This magic threesome gives me the longest lasting mani ever. It's pricey, but totally worth it. And Lippmann bottles are very nicely done.

overall: i have been using hard rock on my nails for several weeks and have experienced less breakage, chipping, and peeling. i use it alone without any color polish, but it makes my nails look great. it just gives it a shine that is not too fake/cheap glossy. the polish stays on my toenails very well- almost up to a month, but not on my fingernails since i wash and use my hands so often. it usually only lasts a week on my fingernails. i wish it lasted longer and i don't know if it works better than other strengtheners since it's the only one i've tried.
package: i like the large, angular glass bottle with the tight black cap. the cap really keeps air out, which keeps the polish from getting thick and dry.
price: it's $18 for 15ml, which is more expensive than the typical nailpolish.

This nail base is GREAT! I have noticed a differents in the strength of my nails already and I have only been using it for two weeks. I have not had a nail peel or chip yet since using it and my nails are normally very weak so that is saying something. It is pricy but I will be repurchasing this. Great Stuff:)

Wow! Can't believe nobody has reviewed this yet! I have had nails that peel forever, except for when I was pregnant and right after. I used Nailtiques religiously for years, but about a year or so ago it just stopped working for me. I've been searching and searching for something else to help and tried a few of the Sally Hansen products which really didn't do anything for me. Then I read a review somewhere of this product, which I went out and bought immediately. I've been using it about a week and can really see and feel a difference in my nails. They are definitely stronger, and not peeling as much. Two still need to grow out a bit to get rid of the peeling edge but the rest of them look great! I am very pleased with this product. It is pricey, twice as much as the Nailtiques, but the bottle is at least twice the size, too. I have to be careful not to get it on my cuticles because it kind of hardens them, too, but the results on my nails are impressive. They feel STRONGER! And not brittle, either. I can't wait to grow them out and see how they do. I'll try to remember to update in a couple of weeks.
EDITED 11/26/06--Well, I'm still singing the praises of this stuff. I have not had one nail break or peel in what now, almost 3 months?!?!?!?! It is the bomb!
EDITED 5/14/07--still singing the praises of this. My nails are still strong and healthy. I will never be without this product (as long as it keeps working for me! lol).