Actually, Russ, it's the B&W CNT series that has been replaced by the 700 series. The B&W 600 series is still in its most recent s3 iteration. I agree that the Monitor Audios definitely have more treble energy and can be considered bright to some people. The B&Ws have a similar, high-energy-treble sound, though I find that it has a more pronounced mid-range than the MAs, which some people like and some dislike.
Never had a chance to compare my Ascends to the MAs side by side. I did compare the Ascends to the B&W 600 and CNT series and preferred the Ascends due to the smoother treble and a generally more balanced presentation (no emphasis on any given frequency spectrum). While most people tout B&W for their detailed midrange and highs, I thought the Ascends relayed the same amount of detail, but just in a less strident manner that drew attention to it. Also, while the B&Ws played lower, I thought that what bass the Ascends put out was more accurate and controlled.
So if anything, the only weakness I found in the Ascends is that of low-frequency omission -- the frequencies that it does play is extremely clean and refined, but that only extends a little lower than 80Hz, necessitating the use of a subwoofer for most bass-heavy music and HT applications.