[jenseng]

to put it simply, browsers are really good (these days) at executing javascript, thus the biggest factor in this test seems to be the large(r) HTML payload.

though to make this a better test, I think you should serve both the JSON and HTML as static assets. after all, we're not interested in benchmarking ERB/to_json/ActiveRecord here, we care about the client side. server-side templating and JSON generation could both be quicker with optimizations and/or different backends.