This HTML form module doesn't try to do everything for you, and thus avoids the primary reason most other form modules suck. (In his blog post on the creation of Chloro, Dave quotes Matt Trout as saying "form modules are... satan". Never have truer words been said.)
This is a pretty simple HTML form validation engine built on Moose. At its core, you define forms as classes using Moose types for field validation. It makes you design in terms of data, not the form presented to the user. It focuses on delivering a strong validation system, and leaves the HTML generation to other facilities better suited to the task (like, say, the templating system you almost surely already have in your application).
Even in its alpha state, I find it preferable to the other options in this domain on CPAN, enough so to use it in at least one production application.
I find that a lot of Dave Rolsky's modules tend to work their way into a lot of my projects, because they are all pretty well done and tend to be pretty ubiquitous in their use. Chloro is no exception.