Customers have become increasingly dissatisfied with the electronic items, the Wall Street Journal reports. In fact, “cigalike” device sales from Big Tobacco companies are expected to plunge 21% for the quarter ending Oct. 31, according to the newspaper, citing figures from Nielsen.

Meanwhile, the Journal says e-cigarettes’ compound annual growth rate is expected to plunge to 57% from 114%, according to Euromonitor data.

“Consumers are disenchanted right now with these products,” said Wells Fargo analyst Bonnie Herzog in an interview with the Journal. “It’s not that different from diet soda.”

The devices reportedly don’t offer the same experience as non-electric cigarettes. For instance, nicotine takes longer to enter the body, which is part of the reason why users are switching back to regular tobacco products.

There’s also pending Food and Drug Administration approval on final rules, which is partially hurting the industry’s sales, according to the newspaper.

“That’s creating stagnation,” Dimitris Agrafiotis, chief operations officer at Mountain Oak Vapors, told the Journal. “We have a big uphill battle if we can’t accurately describe our product.”