They're actually quite good for this genre specifically from my experience, but I can't say I've heard the FXT90 to make comparisons and from what I've read about the two it's hard to say. Depends on your sound priorities and preferences - check out Joker's IEM thread if you haven't already, as he has reviewed both:
http://www.head-fi.org/t/478568/multi-iem-review-293-iems-compared-etymotic-research-ety-kids-added-08-12-13-p-748 He compares the FXT90 to the original GR07 in it's review quite a bit, so if you consider the differences between them and the BE you'll get an idea of how they should stack up. All the GR07 models are tuned very close to one another, so the overall sound and presentation is quite similar. I think I recall some other people here that also have the FXT90 so they may chime in, but I suspect you'd be satisfied with either.