Similar in basic outline to the classic dalek, the imperial dalek has a base colour of white with the sensor pods and power collectors in gold. The imperial daleks don't owe any alliegance to other daleks except the Imperial Dalek itself - later revealed to be Davros himself, the creator of the dalek race. The classic daleks want Davros dead and while they have had an Emperor Dalek of their own, this was a dalek through and through.
The imperial daleks have been upgraded by Davros while the classic daleks retain their original configuration. This has proven to be another source of tension between the two factions.