If you leave the funds in the 401k, it is considered a "pension" for certain legal purposes and has some protections, such as in bankruptcy, that an IRA may not have. Your employer may be able to negotiate for lower cost investments in the 401k; for example, you may be able to buy the "Institutional Class" of the ABC fund for a 0.2% expense ratio, while in a private IRA you might have to buy the "Investor Class" ABC fund with a 1% expense ratio. Lower expenses mean your funds will grow faster over time.
With an IRA you probably have more investment options available to you, some 401(k)s limit investment choices as a way of protecting the employees' retirement funds (by not letting them invest in things that are too risky, for example). If your 401(k) is not diversified (such as, it is heavily invested in one stock, such as the employer's stock) then you probably want to roll it over to an IRA and diversify your investments.
I don't know any reason why distributions would be easier from an IRA than a 401(k), unless your 401(k) provider is just a crappy company that can't process withdrawals, or you are invested in something that is not very liquid.
