i have a blaupunkt DAB 54 in my pickup, can't remember what i paid for it, I have an amplified window aerial. It sounds good when your in a good reception area but the M18 and M1 are terrible for reception, it keeps cutting out. I find the BBC ensamble is the worst for this too!
If mine cuts out on DAB and it can find the station on FM it will switch to FM, but that is even more annoying as it keeps flicking from one to the other and they seem to have different volume levels so your always adjusting the volume.
Having extra stations sounds good, but its a bit like sky, you spend all your time flicking and never actually listen to something.
If your buying a new head unit anyway then get a DAB, but don't buy one for the sake of DAB.