Regards - I also have the Act 3 with Bass management and confirm the comments of Sc53. No problems of any kind in 9 months of operation, and Mondial's customer service is absolutely first rate. Regarding hum, I get the impression that the Act 3 may have been a lot of peoples first AV unit, and the unit is so revealing that there's grounding hum which they never knew was there before. Also, there's the need to ground the cable input which many overlook. Once I put the Majik in line with the cable there was no problem.
I heard the B&K, and can't comment on it's A/V performance, but with music the Act 3 immediately sounded better to me.