I really wanted ActiveResource to work for me, but I had a few requirements that it couldn't meet, like camelCased attribute and resource names, HTTP caching, and the ability to change authentication at runtime without race conditions (since configuration is done at the class level in ARes).
I wrote a small gem called well_rested to replace ActiveResource in my project. It utilizes ActiveModel for validations and generally plays well with Rails. Maybe it will be useful to someone: