Perhaps Im missing something, but I've upgraded to WP 3.5 and Attachments 3.0 and Im still seeing the old media manager - not at all what you've shown in your screen shots. I've tried disabling and enabling plugins etc but with no effect.
Now everything seems to be working still on the Attachments plugin side - but, (and perhaps this is a separate issue) I do get errors when uploading images using the "add media" button. Just red notices, with no real information. That said, on a page refresh, the images that threw errors, appear in the file list.