Some thoughts --
Vanguard has an online tool that compares costs between funds and ETFs. It can be found at https://personal.vanguard.com/us/faces/JSP/Funds/Tools/Funds... IIRC you can input commission costs, frequency of trading, etc. and get a comparison.
One item of interest is whether your broker reinvests dividends for the ETFs.
For many, the lure of lower expenses of ETF make them attractive if the personal conditions are right. Personally, I like mutual funds holding them direct with the fund family.

Bob