Links is the very best directory script that I've ever worked with.

There are scripts which are faster to install, but Links has worked flawlessly for me on a variety of servers. If you follow the instructions, it takes a few minutes to install it and a while to get it tweaked to look and function just the way you want. But that's the beauty of Links 2.0 (and SQL I presume) - that Links is very very flexible so you can make it do exactly what you want. Other scripts which take a few minutes less to install initially don't provide the same ability to easily and fully customize them.

If you're looking for a script you can install in 5 minutes and apply template x y or z that 5,000 other people also use and be done with it, I'll admit you could find a better script for your needs.

If you're looking for a powerful and flexible script for a site that you plan to invest some time in to make it the best it can be, and want a product that you can do virtually anything with customizing from the smallest detail to mods which add major functionality, customized to the unique needs of your site and with a robust upgrade path (Links SQL) for when your site grows, Links 2.0 is a great script.