Dell XPS27 vs iMac

This is not Dell's first all-in-one PC, but it's by far the best and it's worth comparing to Apple's iMac.
It has a 27 inch widescreen with 'Full Quad HD' 2560 x 1440 resolution, a wireless mouse and keyboard and a metal finishing.
The XPS 27 is one of Dell's first products that are equiped with 3rd generation Intel cores (Ivy Bridge). You can choose between a Core i5 and a i7 and if you are a demanding user you can choose the optional GeForce GT 640M Nvidia.
In addition, XPS 27 has a 4 GB RAM expandable up to 16 GB and a 1 TB hard drive (up to 2TB) with an optional 32GB SSD drive.
As for input/output: 4 USB 3.0, 2 USB 2.0, HDMI, Bluetooth 4.0, Wi-Fi.