I'm finding that it's a lot cleaner to use with Javascript. For example, say you have an array of items and you want to create a fieldset for each item, and add an attribute of "data-id", and "data-category" to each fieldset so you can grab them with jQuery later on.

In HAML all you have to do is this...

- @items.each do |item|

  %fieldset{:data => {:id => item.id, :category => item.category}}

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In ERB the equivalent would be...

<% @items.each do |item| %>

  <fieldset data-id="<%= item.id %>" data-category="<%= item.category %>">

  </fieldset>

<% end %>

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It's a lot cleaner in HAML, especially extrapolated out over larger views.