Subjective measure. And I am not uncertain if an improvement has occurred or not.

edit: however, I do not minify on-the-fly, I keep the source HTML, CSS and JS files space and line-break compressed (and variable-name compressed.) The speed increase may be due to less going down the wire, or it may just be faster to process by the browser due to some other mechanism.

Also, having css and JS code within the HTML itself has sped things up too - no external files.

Have a look at the source of http://twitya.com/index.php - I also Gzip that, and this speeds it up as well. I keep a few line-breaks in for readability.

Takeaway: what matters most is having as little data go down the pipe as possible in a compressed fashion, and not worrying about server load - that could be offset by the improvements on the browser.

Also, Gzipping http://hackerbra.in has led to a marked improvement, with its large slabs of text.