The Invesco S&P MidCap 400 Revenue ETF offers an alternative approach to mid-cap investing, outperforming the S&P MidCap 400 but lagging behind the S&P 500. RWK has a relatively low price-to-earnings ratio, making it attractive in a market with premium valuations. RWK's sector allocation is overweight in consumer cyclical and consumer defensive sectors, but underweight in real estate and healthcare.