If you haven't yet, give Future Advisor a look. They offer the same free analysis, but actually are able to figure out what's in your 401k. I have accounts at both Future Advisor and Personal Capital and I find Future Advisor much more useful.
Future Advisor also provides more targeted advice (establish X percentage of portfolio in REITs) for example. Future Advisor also provides more targeted advice based on your designated aggressiveness and target retirement age. Having been through portfolio analysis meetings with financial advisors with both, I prefer Future Advisor's advice.
Personal Capital wanted me to add commodities such as gold, energy, food, and other metals to my portfolio which I'm completely against. If it doesn't throw off income and/or have the ability to give me positions over time, then I don't buy it. Less volatility at the expense of income and appreciation isn't a fair trade; not in my book anyways. Risk isn't the same thing as volatility.