If you "rollover" your old 401(k) to Vanguard, it becomes a Traditional IRA. If you've declared bankruptcy before, or think you might in the near future, you might keep the money in a 401(k) for the added bankruptcy protection. For everyone else, I'd say greater control over your account makes the rollover worth it.
Once you roll over to a Traditional IRA, you have the option to convert some of it to a Roth IRA (paying taxes now at your current tax rate). You also get to pick the funds, rather than being locked into the fund choices. Note 401(k) plans do change funds over time, so you can be forced into new funds when the 401(k) changes.
Don't get overly caught up on 0.02% differences in expense ratio. With $10,000 invested, that's $2 per year. Your percentage bonds and percentage international will probably matter a lot more than $2/year in fees.