TLH only makes sense within Vanguard because other funds distribute capital gains, so not tax efficient.
Only need one “exchange” transaction with Vanguard. Check if Schwab allows something similar with ETFs though. - Schwab doesn’t allow exchanges but does allow 1 trade with unsettled funds.
ETFs:
I can do everything in one place, i.e. my Schwab account. (Mutual funds, on the other hand, aren’t all available for free on one broker.)
I can put limit sell orders. This alone might be the biggest reason to go this way because it won’t require me to track prices closely. Also, alerts.