I see there has been a very very long thread including a discussion on the fx700 and ex1000, but I am wondering what the bottom line answer is for everyone in terms of preference (and the personal reasoning).
I was also curious about the fx850 and how it stacks up (and if the mids are less recessed).
I had the FX500s which had more of a V shape than the FX850s. The FX700s, from what I have read, are similar. So you will get a flatter sound, but with very strong bass.
The EX1000s were considered on the bass-shy side. The FX850s definitely are not that, which is why I would prefer them. I'm a pretty big basshead and the FX850s are strong enough to satisfy my tastes without being overwhelming.