It sure hasn t taken long for the financial giants to hitch onto a new trend in investing and to get some attention for doing so. But the question for the typical investor is still the same: Do active ETFs make sense?

Actively managed exchange-traded funds are fast becoming a hot product, with T. Rowe Price, John Hancock and Vanguard taking steps to enter the fray. Some experts predict the number of active ETFs could climb toward 100 by the end of this year, from 14 at the end of 2009. While that would be a fraction of the more than 900 ETFs, that kind of growth is remarkable considering active ETFs seem to turn the original concept of ETFs on its head.

The original idea behind ETFs was to pick a basket of stocks, bonds or other assets and let them run by themselves for a very low cost. With the active version, managers keep changing the basket of investments and charge extra for the work. Critics say that means investors also have to stay active and watch the funds like a hawk. If the ETF manager does a lot of trading, another advantage of traditional ETFs goes out the window: tax efficiency. Actively managed exchange-traded funds don t have any of the things that are important in ETFs, says Gary Gordon, an investment adviser in Aliso Viejo, Calif.

Firms that offer active ETFs say they combine the advantages of mutual funds and ETFs. You re getting traditional active management in a new, more efficient structure, says Noah Hamman, CEO of AdvisorShares Investments. So what s an investor to do? One answer may be to just wait. Unlike most mutual funds or ETFs, active ETFs don t have a long track record. Until they do, some financial planners advise treading carefully.