There are several separate distributions on CPAN that implement routes dispatching. Below is my attempt in comparing Router::Simple, Path::Router, HTTP::Router, Routes::Tiny and Path::Dispatcher.

    +-------------------+-------------+----------+----------+----------+---------~
    | Name              | Constraints | Optional | Grouping | Globbing | To path ~
    +-------------------+-------------+----------+----------+----------+---------~
    | Router::Simple    |      +      |    -     |    -     |    +     |    -    ~
    | Path::Router      |      +      |    +     |    -     |    -     |    +    ~
    | HTTP::Router      |      +      |    -     |    -     |    -     |    +    ~
    | Routes::Tiny      |      +      |    +     |    +     |    +     |    +    ~
    | Path::Dispatcher  |      +      |    +     |    +     |    +     |    -    ~
    +-------------------+-------------+----------+----------+----------+---------~

    ~-------------------+-----------+------+
    ~ Name              | Subroutes | PSGI |
    ~-------------------+-----------+------+
    ~ Router::Simple    |     +     |  +   |
    ~ Path::Router      |     +     |  +*  |
    ~ HTTP::Router      |     +     |  -   |
    ~ Routes::Tiny      |     -     |  -   |
    ~ Path::Dispatcher  |     +     |  +   |
    ~-------------------+-----------+------+

* via Plack::App::Path::Router (thanks to Arun Prasaad)

Explanations

Constraints

Ability to limit a capture to a specific regexp. For example, we want to match /articles/1 but not /article/foo, so we add a constraint like \d+.

Optional

Ability to add optional captures. For example, we want to match /blog/2010/01 and /blog/2010 without specifying an additional route.

Grouping

Ability to capture not just between slashes. For example, we want to match /hello-user, capturing hello and user.

Globbing

Ability to capture path using globbing. For example, we want to match /book/title/that/constains/slashes without worring what goes after title.

To path

Ability to build a path from a route. For example, we don't want to specify paths directly in the templates, so we can use something like

    build_path('article', id => 1)

and get /articles/1.

Subroutes

Ability to mount subroutes on a specific route. For example, we want to add routes that all start with /admin/.

PSGI support

Easy integration into PSGI frameworks. Ability to match against PSGI environment.

Disclaimer

If you found any error, please correct me.