There is no difference between the SmartSeries 6000 and the SmartSeries 6500 beyond the colour of the handle – the 6000 is purely the replacement model for the 6500 which, while technically phased out, is still on sale. In terms of features and settings, they are identical. You’ll usually find the SmartSeries 6500 on sale in the same places as the SmartSeries 6000, with the 6000 costing a little more usually. With that in mind, it makes sense to go for the 6500 if it’s available.