over the long term small caps tend to outperform large caps. The ETF version is VTI.
To see this point, pull up a long-term chart of VB (small caps) versus VTI (total market). But also note how VB is more volatile. If a bear market develops, a switch to small-caps might be regrettable.
The best way I know to beat the market is to sell a put option ITM and get assigned. Then you have the option premium received plus market performance. For extra credit, invest the premium received.
E.g. At this moment, $259 December 15 SPY put options can be sold for $4.11 per share (or $411 per contract). If you get assigned, you've essentially bought SPY for (259 - 4.11=) $254.89 at a moment when the market price was $257.60, a full 1% discount. Hold those shares for a year and you will have outperformed the person who just bought the index by 1%, minus transaction costs/taxes, regardless of if the market rises or falls.
Note that with this strategy there is a risk the market surges higher in the next few weeks, and your put expires out-of-the money, leaving you with $411 in your pocket, but no shares. That's the risk you're getting paid 1% in 35 days for, and in that event you would play again until assigned, earning ~1% per month until eventually getting assigned on a dip.
Side note: SPY is cheap, but for what it is it is incredibly expensive. 0.09% for SPY. VOO is the same thing and costs 0.04%. ;-)
The difference may be that for whatever reason, VOO has a thin, relatively illiquid options market with $0.60 wide bid-ask spreads for next month's options (!) and few available strikes. SPY, in contrast, has dozens of strikes and spreads of 1-3 pennies per contract. The five one hundredths of a percent difference in fees would be quickly made up on the first trade I described above. For example, the same strategy played on VOO at the $240 strike (the only December ITM strike available) and selling at the midpoint of the bid-ask would yield only 0.3%, which is not worth the trouble. Note how the 0.7% net difference in put-purchase-strategy outcomes would cover 14 years of the difference in fees between SPY and VOO.
This has always struck me as a paradox. SPY is the bigger and more popular ETF despite higher fees. Because it is bigger and more popular, it has the better options market. Because it has the better options market, it is bigger and more popular.
Bottom line: if you're just clicking "buy", VOO is the better investment. If you purchase with puts as described above, definitely use SPY.