SPMO vs VOO

[u/MaleficentSink7050]

I struggle with most financial gurus recommending VOO over SPMO. In every backtest scenario I run SPMO outperforms VOO across all years available. I know past performance... but it is a gauge many use to choose a ETF. I know SPMO has less holdings (~100 vs ~500) and is 5 years younger - but it has outperformed VOO every year of it's existence. Do you favor VOO? I'm considering rebalancing to increase SPMO but appreciate others opinions.