Newer cameras generally mean newer sensors which are generally better in low light. Pikeys D70 was a good buy though, the cameras in that range (D70, D80, D90) are much nicer to handle and are made much more substantially.
Generally I'd rather go for an older, higher quality camera but just remember it's more about you than the camera. Also if you are just starting out you probably won't even notice the difference so go for the one that is easier to handle. If you ever get frustrated with it or want higher specs you can always buy and sell on ebay once you know the game.