> OP said that he found it easy to contribute despite the 
  > fact that he didn't have prior experience in rust

Just yesterday I was talking to the person who contributed WebGL support to Servo (a relatively recent and substantial patch), and they reiterated this sentiment. It was their first time ever using Rust, and although they'd reluctantly done some C++ in the past their primary programming language is Javascript. They were pleasantly surprised at how easy it was to contribute such a large patch, and had bountiful praise for how well-organized the codebase is. The patch actually bounced a few times, and they were also very pleased at how the core contributors continued to work with them over the course of days to track down the breakage and keeps things moving.

This person's primary interest is in virtual reality, specifically WebVR (http://webvr.info/), and given Servo's incredible benchmarks so far they're very optimistic about its ability to advance the state of the art of virtual reality on the web.

Their biggest complaint was build times. Yeah... we're working on that. :)