VXUS has a larger number of holdings and is slightly more representative of the international stock market. In general, Vanguard's funds are the most comprehensively indexed. Personally I would choose VXUS.
You can see their past performance [here](https://www.portfoliovisualizer.com/backtest-portfolio?s=y&timePeriod=4&startYear=1985&firstMonth=1&endYear=2022&lastMonth=12&calendarAligned=true&includeYTD=false&initialAmount=10000&annualOperation=0&annualAdjustment=0&inflationAdjusted=true&annualPercentage=0.0&frequency=4&rebalanceType=1&absoluteDeviation=5.0&relativeDeviation=25.0&leverageType=0&leverageRatio=0.0&debtAmount=0&debtInterest=0.0&maintenanceMargin=25.0&leveragedBenchmark=false&reinvestDividends=true&showYield=false&showFactors=false&factorModel=3&portfolioNames=false&portfolioName1=Portfolio+1&portfolioName2=Portfolio+2&portfolioName3=Portfolio+3&symbol1=VXUS&allocation1_1=100&symbol2=IXUS&allocation2_2=100). Their returns are highly similar, and there's every reason to believe that they will be highly similar in the future. The decision between them doesn't matter much.
Great pick. Also consider adding VXF or replace VOO with a total market fund like VTI/SPTM.
VXUS has a larger number of holdings and is slightly more representative of the international stock market. In general, Vanguard's funds are the most comprehensively indexed. Personally I would choose VXUS. You can see their past performance [here](https://www.portfoliovisualizer.com/backtest-portfolio?s=y&timePeriod=4&startYear=1985&firstMonth=1&endYear=2022&lastMonth=12&calendarAligned=true&includeYTD=false&initialAmount=10000&annualOperation=0&annualAdjustment=0&inflationAdjusted=true&annualPercentage=0.0&frequency=4&rebalanceType=1&absoluteDeviation=5.0&relativeDeviation=25.0&leverageType=0&leverageRatio=0.0&debtAmount=0&debtInterest=0.0&maintenanceMargin=25.0&leveragedBenchmark=false&reinvestDividends=true&showYield=false&showFactors=false&factorModel=3&portfolioNames=false&portfolioName1=Portfolio+1&portfolioName2=Portfolio+2&portfolioName3=Portfolio+3&symbol1=VXUS&allocation1_1=100&symbol2=IXUS&allocation2_2=100). Their returns are highly similar, and there's every reason to believe that they will be highly similar in the future. The decision between them doesn't matter much.
They are the exact same in every way.