ITOT and VTI are highly diversified ETFs. Investors prefer diversified assets because they tend to be less volatile.
The fund tracks stocks in the CRSP US Total Market Index. VTI is one of the biggest ETFs in the world based on asset net worth.
VTI has always outperformed ITOT because it tracks small and mid-cap stocks. Besides VTI’s slight performance edge, they are largely the same in other aspects.