If you have $205 to throw away, get the new model, which is 0.1 GHz faster, and comes with 8GB instead of 4GB.
Or you can get the “old” model refurbished (same as new from Apple), and buy 8GB of memory for about $57 from OWC, or 16GB for about $162. And still come out ahead in dollar terms, and/or with twice the memory.
The Ivy Bridge processor in the new model offers the Intel 4000 integrated graphics (vs. Intel 3000 in the old), but in all my past photographic testing, the “faster” graphics are not of any benefit. Gamers, etc might care though.
There is one “worth having” feature on the new model: two (2) USB 3.0 ports on the new model, which makes higher speed external drives possible. Still, that is an “intended usage” decision.
Seems like a no-brainer to me.
Please buy either through my site links.