You get a 20% faster hard drive, 90 extra GB HD, and illuminated keyboard. And costs 25% more. I bought the top end MB myself and need the extra HD space but also want to buy a 7200 rpm, so I sometimes wish I would have bought the $1299 model and used the difference for 7200 rpm HD and more memory. I don't really need the lighted keyboard. And the 20% faster CPU isn't nearly as big of a boost to system performance as doubling the RAM.
So it really comes down to the keyboard in my opinion. Either one needs the RAM upgrade. And spending $100 on the HD will net a faster system. Either system require you upgrade the HD and memory so it really truly comes down to how bad you want the illuminated keyboard.
Good luck whichever way you go.