The NPD Group reports 63% US customers intending to buy a smartphone in the next 6 months show most interest in an Android-- but 44% of both smartphone owners and customers intending to buy a smartphone also show interest in Windows Phone 7 devices. 

The analyst describes Android as a "juggernaut" making part of at least 50% of all smartphone purchases in the last 3 quarters, but it sees competition from the iPhone and the "nascent" WP7. 

Around 33% of Blackberry device owners are also "most interested" in Android as a next smartphone purchase. 

WP7 has one main problem-- lack of consumer awareness. NPD says 45% of potential customers "are still not aware of Windows Phone 7," while 50% lack interest in WP7 (46% of saying they "don't know enough about it").

OS ecosystem lock-in is the 2nd most offered reason, with 21% saying they have "too much time or money invested in another smartphone OS."

NPD concludes the Microsoft mobile OS has potential to "chip away" at Android-- but only with "the right marketing mojo, apps portfolio and feature-rich hardware." 

Go Android on Top for Now but Consumers Also Eyeing Windows Phone 7 (NPD Group)