Long-time readers will know that I recommend these funds for people who don’t want to spend too much time on investing. See Kiplinger’s article.
I like Vanguard’s target-date funds because of their low costs. While they tend to be more conservative than other company’s target-date funds, an investor willing to take on more risk could easily do so by investing only in the longest-date fund, no matter when that investor plans to retire, or by supplementing the target-date fund with a pure-stock index fund.