Nothing, purchased this year, only have a loss.
Oh that makes the decision easy then. Just sell everything*, harvest the loss, and buy in Vanguard**.
*If you do not sell everything then you may incur a wash sale that will reduce your deductible losses. I assume this point is moot because you would be selling everything.
**To claim the loss on your taxes you must not buy a "substantially identical" security in the next 30 days in
any of your accounts. Neither the IRS nor Congress has clarified what "substantially identical" actually means but many people take it to mean that any mutual funds that track different indices are not substantially identical.
So you can either sit out of the market for 30 days, or buy a similar fund that tracks a different index. Such as VFIAX which tracks the S&P 500 index. This is a pretty good approximation to VTSAX. If you want to you can also buy VEXMX (that's the investor share class ticker) which tracks the S&P 500 completion index. When you hold VFIAX and VEXMX in an approximately 4:1 ratio, you will get VTSAX's performance within a very small margin of error.
This whole VEXMX business is completely optional, VFIAX will do just fine.