640m Benchmarks 3DMark11

Not really, you're getting a faster CPU too for $200.

http://www.notebookcheck.net/NVIDIA-GeForce-GT-650M.71887.0.html

http://www.notebookcheck.net/NVIDIA-GeForce-GT-640M.71579.0.html

3DMark 11: 1708 vs 2085
3DMark Vantage: 6577 vs 8131
Deadspace 3 High: 54fps vs 69fps
etc

You're looking at 20-25% difference.

 

The Fusion drive would be my priority for the 21.5". I keep trying the 21.5" without the fusion drive in different stores and it's a beachball fest every time; painfully slow.

 

There are some visible differences between them. But yes the master one is the fusion drive. So i suggest you, if the budget is limited to opt for fusion drive instead for the high end 21.5"