The Radio Listener's Guide is a highly-respected annual publication which, among other things, reviews all radios currently on sale.
The DAB personal radios listed in the 2013 edition are as follows, with their rating (out of 5) in brackets:
Roberts SportsDAB 2, £80 (5)
Technika DAB 211PT, £27 (4.5)
Asda E80210, £30 (4)
Roberts Robi, £30 (4)
Pure PocketDAB 1500, £70 (4)
Pure Move 2500, £80 (3.5)
Aigo DAFM001A, £40 (3)
Bush Pocket DAB/FM, £33 (2.5)
So, for the very best quality (at a price) the Roberts SportsDAB 2, looks to be your best bet. To save money though, a trip to Tesco (for the Technika DAB 211PT) might be in order.