I prefer the "diamond" tweeters.... hard to describe how they do it, but even more resolution while at the same time being more relaxed sounding.... less ringing in the midrange, too... a worthy upgrade...
we did a shootout here a couple years ago where we swapped tweeters back and forth and I don't think anyone picked the Be tweeters... the diamonds are much more expensive tweeters to buy/make (I know, having bought some to help customers upgrade during the transition from Be to Diamond)