Is there a big difference between the KRK rokit 5 models?

[D-TreeBeats]

I'm buying some monitors on ebay and there seems to be two different models for the KRK Rokit 5 monitors. It seems the curved monitors are newer and the box monitors are older. I'm just wondering if there is really any significant difference. Thanks~!

 

[ObiK]

Both would sound a bit different as they are 2 different generations of monitors. I'd go for the newer ones if you can.