Updated models with AMD graphics options expected in early 2017.
Apple Notifying Aperture Users of Impending Removal From Mac App Store
"When Photos for OS X launches this spring, Aperture will no longer be available for purchase from the Mac App Store. You can continue to use Aperture on OS X Yosemite, but you will not be able to buy additional copies of the app.Aperture users will be able to continue using the software on OS X Yosemite following its discontinuation, although the app will no longer be available for purchase on the Mac App Store and new feature updates are not planned. Aperture users can migrate their photo libraries to Photos for OS X, including photos, adjustments, albums and keywords.
You can migrate your Aperture library to Photos for OS X, including your photos, adjustments, albums, and keywords. After migrating, your Aperture library remains intact. However, Aperture and Photos do not share a unified library, so any changes made after the migration will not be shared between the apps."
Photos for OS X will be available this spring for OS X Yosemite.