An interesting, lengthy article regarding equal weighting vs. cap weighting. As you probably know, indexes are typically weighted by market cap. A few years ago, there was an idea to create an index and weight it equally across sectors. This was met with resistance because it seemed like a lot of transaction cost to keep the weighting proper. However, backtesting proved that the idea had merit and off it went.
The article I'm referring to can be found here. It's titled "Equal Weight Indexing: Five Years Later". But the bottom line here is if you bought RSP (Rydex S&P Equal Weight ETF) and SPY at the inception of RSP, what ETF did better?

As you can see, since inception, the equal weight portfolio has outperformed the cap weight. But wait a second, 2003 marked the beginning of the last bull market, so how did we handle a down turn? I took the same chart and shortened the time frame to 6 months (October 29th 2007 - present day). This should encompass our recent "bear" (cough!) market. The performance was about even. I sliced it a few more ways and the only losing period I could find was 1 year and that's April 2007-April 2008 where the RSP was down 9% and the SPY was only down 6%.
The next measurement I was curious about was beta. For longer term holdings, I'm interested in low beta, as I get my higher betas through speculative plays. The beta registers at 0.9 (and of course, the SPY beta is 1.0). So for lower beta, you're usually outperforming the S&P 500. The yield on the SPY is a bit higher 2.11% vs. the RSP at 1.58%.
The great thing about all of these new ETFs being introduced over the last couple of years is that we finally get to see the various theories in action. Five years is a good enough track record for me to consider dipping a toe in and mixing it in with a cap weighted ETF or two. Many more of the concept ETFs that don't die in the next 5 years will be worth the same analysis.