Phil Sturgeon, who has contributed to numerous valuable PHP related projects, is doing Ruby nowadays. In an article he wrote for Sitepoint compares Ruby with PHP.

... I thought it would be interesting to have a slightly more fair comparison, from the perspective of someone who really enjoys writing both PHP and Ruby, and has done so for years. The aim here is not to find out which is “better”, but to point out a few key things I like about Ruby and its ecosystem.