It's still better that Dell and Apple allow end users to add memory modules and memory cards after the initial purchase. It's nearly impossible to do that with a 16GB iPad that costs US$499.
I looked into how much adding RAM in the configuration/selection/customization processes when ordering from Apple and Dell online several times in the past one year so, and it always seemed more than twice as expensive as it would cost by ordering separately from Newegg.com.
A Samsung or Hynix 8GB DDR 3 module for laptops now costs only about US$40 in Seoul.
Right now, Apple charges US$300 more to replace two 2GB DDR 3 modules with four 4GB DDR 3 (4GB -> 16GB) for iMac.