From Wikipedia:
An average over 100 in a match in the PDC World Championship has [since the split] been achieved 58 times, compared to 20 times in the BDO World Championships, despite the BDO tournament's longer history. 9 different men have achieved an average of over 100 in the PDC tournament, compared to 8 different men in the BDO tournament since the split in 1994.
The Grand Slam could, in a few years, start to settle the argument a bit.
Thing with the BDO is that, outside of the top four or five players, there's some shocking darts going on - mainly an inability to hit doubles. If Martin Adams could properly conquer his nerves, he'd be a good bet for the top 16 of the PDC. Likewise John Walton, if he can get back his form of a few years back.
Having seen plenty of games, there's definitely and element of 'raising your game' when playing against someone like Taylor - averages go up.