Chaos Warhounds are 6pts each, so taking a long time to paint them isn’t a great idea. These guys are meant to cover the more expensive Chaos Warriors behind them, or threaten/distract your opponent. With Ld:5 they are easily shot up and sent fleeing by your opponent. If he doesn’t target them, he shouldn’t worry about them anyway- they can no longer negate ranks in 8th ed with a simple 5-wide unit; and they’re only going to cause panic tests as they flee through your army.
So why take them then? They’re fast, and so can charge your opponent’s light stuff on turn 2: warmachines, solo characters, and fast cav. They redirect well too – put at weird angles and whatnot. But they’re best used to screen the expensive stuff behind them – their screen will confer a -2 shooting modifier. So go crazy with Warhounds – not as good as they were in 7th ed., but still able to cause… er…chaos.