I like the intra-day liquidity of ETFs if I'm shifting assets. It's frustrating having to wait for the market closing price on a Mutual Fund, especially over the past few years when you could see relatively large price swings during the trading day. It was especially frustrating to have to wait several days for the cash to clear before buying the shares in the other fund, for the same reason.
On the flip side, mutual funds appear "safer" to me because one extra level of custodian risk is removed. With the ETFs, I have broker risk as an extra layer over the unavoidable fund-company risk.