But, as Kobak and other financial advisors caution, all investment products come with advantages and disadvantages. And because the potential downsides of ETFs might escape casual inspection, they should be vetted as thoroughly as any mutual fund.
"You have to do your homework with both," Kobak said, whose clients typically have about 80 percent of their portfolio in ETFs.
There's no question that investors' romance with ETFs has continued unabated. While traditional, open-end mutual funds saw roughly $153 billion in outflows this year through August, ETFs reeled in nearly $142 billion of new money, according to investment research firm Morningstar.
Separate research suggests that millennials — who now represent the largest generation in America, at more than 75 million strong — are driving much of the ETF love.
Charles Schwab's 2015 ETF Investor Study revealed younger adult investors (those ages 18 to 35) have 41 percent of their portfolios in ETFs, compared with 25 percent of Generation Xers and 17 percent of baby boomers.
Moreover, the study shows that 70 percent of millennials see ETFs becoming their core investment type in the future. That compares with 46 percent of Gen Xers and 24 percent of boomers.
For fans of ETFs, the benefits are no-brainers.
For starters, they generally boast lower costs. Morningstar data show the average expense ratio for all ETFs is 0.56 percent, compared with 1.18 percent for traditional mutual funds if you include both actively managed (professional fund managers pick the investments) and passively managed (think index funds).
Even actively managed ETFs — of which there are fewer than 60 — come with a lower price tag. Their average expense ratio is 0.77 percent, compared with 1.2 percent among actively managed mutual funds, which number in the thousands.