Premium product
Apple have always been a premium vendor, they are the current market leader and have a much wider selection of apps available than any of the competitors.
Anyone looking to compete with them will either have to do so on price (see hp) or offer a significantly better product for the same price.
Motorola seem to have the right idea, and are heavily discounting the Xoom, the 32gb model can now be had for under £300 compared to the 16gb iPad 2 at £400, and their tablet is android based so it has far less app availability problems than HP or RIM faced.
These vendors need to take a punt, and offer their tablets at break even price in the short term to gain market share.
If given the choice between the market leading, premium ipad2 or a lesser known non premium brand with less apps available for the same price, what would you choose?