I haven't heard the BP1.5 or internal MC card, so no opinions there.
Take analog gear reviews with a bigger grain of salt than the rest IMO. There's so many variables - turntables, cartridges, tonearms, isolation, and on and on.
To say there was no sonic difference between the stages is very surprising, but it could be a case of something amiss in the setup. The best way to evaluate the stuff is to demo at home.