Agree - DO NOT RAID the fund and use it for anything else except retirement. Tax-deferred earning accounts are a precious resource!
I do not (necessarily) agree with rolling it over into an IRA. My workplace 401k has very low cost index funds, such as S&P 500 with a 0.01% fee. Yes, 0.01%(!) - through Blackrock, and lower than Vanguard. Many fund managers are lowering their fees to compete with Vanguard. I love Vanguard, and I have a post-tax account with them, but there are some lower-cost or equal-cost options out there. Many 401k plans also offer the ability to purchase individual ETFs (such as vanguard) through them.
The main point though: 401k plans have a higher level of liability protection in many states compared to an IRA if you ever get sued or are entangled in previous, future, former or current spousal litigation.