Apple's iPad is gaining on Amazon's Kindle as a general-purpose e-reader, according to ChangeWave Research, more evidence of the irrepressible popularity of the Apple tablet.

The iPad's share among e-reader owners is up 16 points to 32 percent since August, roughly a mirror image of the Kindle, which has dropped 15 points to 47 percent, according to a ChangeWave Research survey of consumers highlighted in a research note released today.

The rest of the market is comprised primarily of the Sony Reader at 5 percent and the Barnes & Noble Nook at 4 percent.

&39'Very satisfied&39' rating for iPad is high compared with the Kindle.

iPad and Kindle e-reader popularity is trending in opposite directions.

And ChangeWave said there are some distinct differences between how the iPad and Kindle are used as e-readers--not too surprising considering they are radically different designs (6-inch monochrome screen on the Kindle versus 9.7-inch color on the iPad) and price points (the Kindle is about one-third the price of the iPad).

A sizable 93 percent of Kindle owners are more likely to read books on their device, compared with 76 percent of iPad owners. And iPad owners are nearly five times more likely to read newspapers and magazines than their Kindle counterparts, and 15 times more likely to read blogs and news feeds, according to ChangeWave.

For the holidays, e-Reader demand remains strong, with 5 percent of respondents saying they are "very likely" to buy an e-Reader and 10 percent "somewhat likely" over the next 90 days, the market research firm said.