HI Nicknoxx; personally I wouldn't have DAB in a car myself. Two main reasons, firstly unless you are in a strong signal area, like a large city, you'll get drop outs of signal. Secondly the quality of the audio is far worse than any FM signal (due to the low bit rate of the system, which is due to too many channels crammed into the restrictive bandwidth available). It's not too bad on speech only channels but still sounds a little 'digital'. Classical music channels, forget it.
But of course it's your choice. DAB still hasn't taken off like those in charge would have liked. Their main reason for introducing it was to shut down and free up the FM band and sell it off. There are estimated to be at least 10 million FM radios in cars in the UK and I doubt the government would ever pay to replace all these free of charge! Almost impossible due to some of the in-dash sets now installed in modern cars.
Of course it's your choice at the end of the day.
Mike, retired radio and electronics engineer, and car radio/hi-fi repairer.