well, i can in fact comment on most of your questions.
i bought 181 backlash after losing a 174 baker in the backcountry.
as you assumed, 181 backlash just felt too long when in my touring boots (dynafit zzero 4 pebax). that means, a little sluggish to turn in tight spots. might as well be my skill level ;-). but most important and relevant, they were too long in kick turns.
also, my legs are rather short, so i have short levers to turn a long ski.
i did demo 174 and 181 sideshow. same thing, sideshow 174 feeling spot on, 181slightly more stable but too long. i did also demo a 174 hardside. to be honest, they felt a bit like a pair of doors on he groomers. nice offpiste in long arcs, though, but too much work for short turns (read: euro wigggle turns). great float. quite a difference compared with sideshow. sideshow very close to baker in terms of feel.
for whatever reason, i bought a 178 steadfast then. no kidding. fitted them with dynafits. idea was to have something in the baker/backlash/sideshow ballpark from a different maker.
brief description: very stiff ski, even longitudionally. rocker s long but subtle and has a strange pattern, lessens again towards the tip...
steadfast live up to their name, very good stability, great for blasting through crud. edge hold is race ski like. no speed limit. hard to bend into tight turns in moguls/skied out offpiste for me, might be my lack of weight or lack of boot. float, well, not too great. in powder no issue, but in anything breakable or more dense i missed any rocker like feel.
summary, if you like the K2 feel, stay away. if you want a GS ski with added width and subtle rocker for some offpiste excursions, there it is.
next and current ski is a 174 coomback. note that 174 coomback is longer that other 174 k2 skis. i like them for their medium/soft flex and forgivingness. wants to be ridden smoothly, not pushed. skis well in most anything offpiste. okay on groomers. sideshow is much, much better for groomers. actually, sideshow is as much of a groomer ski as i will ever need. nontheless, i went for the coombacks for the better float and more forgiving ride. i might be adding a backup for spring touring/ski mountaineering and the occasional groomer day with friends at some point.
Edited by snowdan - 2/8/12 at 12:48pm