Money-market funds are yielding next to nothing these days. So perhaps it's not surprising that an exchange-traded fund claiming to be a better-paying alternative has attracted a ton of cash. But the question is, does this ETF really pay off?

Bond powerhouse Pimco launched its Enhanced Short Maturity Strategy fund (MINT) late last year, but it really took off during the stock market's spring swoon. Like most money-market funds, Pimco's ETF invests in a portfolio of short-term corporate and government bonds. But it is offering a yield of nearly 0.8 percent, a nice jump from the minuscule 0.1 percent yield that large money-market funds average. The reason: While the ETF doesn't exactly go overboard on risk, it does invest in lower-quality and longer-term assets than money-market funds. The overall result is higher yields, and Pimco manager Jerome Schneider says he expects his ETF to retain the yield edge even when interest rates rise.

But don't plow all your cash into these products just yet. There's the chance that the ETF's price can fall (a money-market fund, under most circumstances, keeps its price stable). Investors also have to pay a commission when they trade the ETF.

Don Dempsey, a financial planner in Williston, Vt., says he's putting cash in another alternative: a high-yield checking account, now earning 0.5 percent. At this point, he says, the ETF is almost not worth it.