I'm a beginner at keyboards and I'd like to know whether I should get a Yamaha PSR-282 or a Yamaha PSR-270.

Is the PSR-282 an upgrade of the PSR-270, ie, does it have all the features of the PSR-270 and have newer features? Or is the PSR-282 a new design with very little to do with the PSR-270?

In either case, which one should I get?