The Burton Flight Attendant deserves to be in every freerider's quiver. I picked up my first FA last year and quickly fell in love with it. From powder days, steep lines, cliff drops - the FA can do it all and has proved it's worth year after year. Burton really paid attention to detail, and from everything from the tip/tail clips to the board connectors, everything is top notch quality and works well in all conditions. The Channel mounting for the bindings is absolutely the best as it offers unlimited mounting angles and stance options, which other mounting systems don't offer. It also includes pucks for mounting the bindings which is about a $50 value and works best with Voile, Spark, or the Burton Hitchhikers (which I would also recommend). I would rate it at a 8/10 flex. It does have a pretty narrow waist width, so keep an eye on that if you have boots in the 10+ range.
I'm 5'10, 190lbs, 10.5 boot (in the Imperial with footprint-reduction) and ride the 158cm split.