Hugh_Conway_jrCAST is build on the notion that Pin bindings are not reliable enough ... maybe this was true in 2010 ... but its 2016 son!
The Beast and the Kingpin now fill the hole in the Pin binding market for High din binders. Even the G3 Ion is a solid contender.
I personally ride ions, and since swapping out the heal piece with the 2016 update, I have had no issue with them (that fix was for uphill performance ... that being said, it depends on the level of performance you are looking for.... how hard do you really huck your meat? now, there is a difference in the release style..so that may appeal to you more.
Ehhh, depends on how much inbounds skiing you are looking a doing. I've skied the Kingpin inbounds a fair bit, and my roommate had the Beasts on his daily drivers. Sure you can do it, but I don't totally see the point. And regardless, I'd still feel like I was rolling the dice on my knees.
And I disagree, I think a big part of the reason CAST exists is a safety aspect. I know plenty of people that only ski FKS's, they won't buy other bindings. The CAST system allows you to still have the proven retention and DIN release (and lateral release, and elasticity) of your favorite alpine binder. I understand why guys combining pretty big tours with heavy hucking are on that system.
As for the Ions, hope that 2016 heel is the real thing. I've got more than a few days on the 2015 ones, and one of my partners is on them full time. Not impressed. Risers get floppy and the break pops down like mad.
patagonialukeThe CAST system caught my interest not only due to the fact that you get alpine binding downhill performance when touring (which may not be a big deal anymore due to said advancements in tech bindings) but also because I will likely be splitting my time between resort and BC, so the idea of being able to have full on alpine binding when I want was appealing. I am just getting started as far as BC goes so I'll probably be doing mostly resort skiing for the first season or so.
Honestly that's the biggest and best argument for CAST I've seen. That said, if you are doing minimal touring, a frame binder will be cheaper, and something like the Guardian will ski just fine inbounds.