The Invesco QQQ Trust and the Vanguard S&P 500 ETF are both reputable and popular funds that track major market indexes. Many investors hold both funds and face decisions about how to allocate between the two.
There is some overlap between the two ETFs, but they ultimately have different characteristics and historical performance that would make each better suited for different roles in a portfolio. Which is the better buy depends entirely on what an investor is hoping to accomplish.
QQQ and VOO are both high-quality funds, and they are similar in many ways. Both have over $100 billion in assets under management, and both have relatively low expense ratios. There is also substantial overlap in holdings, with the two funds sharing Apple, Microsoft, Amazon, Facebook, and Alphabet among their top 10 largest positions. QQQ and VOO are both highly liquid, with 0.01% average spreads high daily trading volumes.
Source Fool.com