Reports claim that Asus is shipping somewhere between 400,000 and 500,000 units of the Eee Pad Transformer per month, which is pretty impressive, especially since Asus appears to have orders for up to 4.5 million units for the second half of the year. You could be very pessimistic and say that shipments and orders do not equal units sold. However, the Transformer appears to be a bright light in what has been a very dark environment for non-iPad tablets so far.
Asus is quiet about any numbers, but we know that the Samsung Galaxy Tab and the Motorola Xoom were not exactly blockbusters. the most successful tablet next to the iPad may have been the Blackberry Playbook, which strongly leverages the Blackberry platform as an incentive for Blackberry users.
The most promising candidate to rival the iPad appears to be the rumored Amazon Kindle tablet that could debut sometime during this quarter. If platform is what makes a tablet successful, then Amazon should have the best shot at an Android tablet these days.