Not all eyelash curlers were created equal, but it's more a matter of how the curler fits one's eye shape than about quality of the tool itself. My first curler was the legendary Shu Uemura and when I started using it after a lifetime of resistance it was a revelation. Eventually, though, I realized that other curlers might be better for my eye shape (round and sunken) and lashline (very full and requires more curl in the outer corner.
My two favorite curlers right now are the Le Metier de Beaute ($18, at Neiman Marcus, Bergdorf Goodman and select Nordstrom locations) and this one from Kevyn Aucoin. I use them interchangeably and can't feel any difference in performance, thought it seems the rubber pad on the Kevyn Aucoin is firmer and lasts longer before it needs the replacement pad that comes in the box.
Which brings us to my one big issue with eyelash curlers in general (not just the Kevyn Aucoin). I would have been happy to pay significantly more for a sturdy well-made curler that is supposed to last for years upon years (just like makeup brushes, a pair of good tweezers or a crystal nail file). I wouldn't mind buying rubber pad replacements regularly had they been available for said mega-curler. However, even the best companies only offer these flimsyish contraptions that come with one set of extra pads and tend to lose their springiness or get mangled pretty easily. Still, even with their tendency to not last a lifetime, most curlers still outlive their pads by a couple of years, so replacing them is way too wasteful.
I do love the Kevyn Aucoin lash curler and have every intention to keep one in my possession in rotation with the LMdB. It's a great tool and a good value for the money.
Kevyn Aucoin Eyelash Curler ($20) is available from Bergdorf Goodman (in store only), Barneys, beauty.com and dermstore.com.