FORTUNE -- As the Galaxy S4 rolls out in the U.S. this week, Samsung is likely to experience its fourth and biggest wave yet of smartphone buying, according to a proprietary ChangeWave poll of early-adopter types conducted between March 21 and April 2.
The results from the survey of 4,011 ChangeWave members, which we obtained Saturday, were released to subscribers two weeks ago. Of the 566 (14%) respondents who plan to buy a smartphone in the next 90 days, 153 (27%) said they expected to get one of Samsung's. Of those buyers, 81 (53%) planned to get the new Samsung S4.
Although interest in Apple's (AAPL) iPhone continues to "settle back," according to ChangeWave, from its peak after the September launch of the iPhone 5, Apple still leads all smartphone manufacturers in terms of North American demand. More than 225 (40%) of the respondents who planned to buy a smartphone in the next 90 days said they expected to get an iPhone (see chart below).

Note that the survey was taken before Apple's April 23 conference call in which CEO Tim Cook suggested that there may not be any new Apple products before September. It's not clear whether those potential iPhone buyers were still anticipating a new model in July.
Meanwhile, Apple continues to lead the field in customer satisfaction, with 70% of iPhone owners reporting that they are "very satisfied" with their phones. Samsung came in second at 54%. See chart.

ChangeWave is a division of 451 Research.
The latest ChangeWave poll finds Samsung and Amazon stuck in single digits
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The numbers are somewhat lower in a follow-up survey posted Tuesday under the headline Who Poses the Biggest Threat to Apple's iPad?
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Philip Elmer-DeWitt - Jun 5, 2012 7:20 AM ET
Six months after its release, 56% of future smartphone buyers say they're getting Apple's
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Philip Elmer-DeWitt - Apr 11, 2012 12:15 PM ET
Apple's new tablet scored even higher than the old. Heat-gate was a nonissue.
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Philip Elmer-DeWitt - Mar 13, 2012 9:01 AM ET
Chief complaints: lack of volume control or camera and that the battery life's too short
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Philip Elmer-DeWitt - Feb 2, 2012 6:02 AM ET
Interest in the Galaxy Nexus is high, but the iPhone still leads in customer satisfaction
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Philip Elmer-DeWitt - Jan 9, 2012 7:07 AM ET
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Philip Elmer-DeWitt - Dec 1, 2011 7:00 AM ET
What manufacturers are going to give Apple's iPad a run for the money?
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Philip Elmer-DeWitt - Nov 22, 2011 2:01 PM ET
Pent-up demand for the new Kindle is even stronger than for the iPad 2
In a note to clients issued Thursday, RBC's Mike Abramsky shares the results of a ChangeWave survey of 2,600 early adopter types. Two key findings:
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Philip Elmer-DeWitt - Nov 9, 2011 8:38 AM ET