I would say it depends on how much boot backing your going to do. If you plan to do a couple runs a season and if it's easy to ski out of the slack-counrty area your looking at, I say go regular bindings. Bootpacking does suck but who cares when it's a 40 min hike. Plus you still have to buy multiple pairs of bindings which is not cheap option (park bindings and AT). If your trekking to slack-country on a daily basis I would consider the quiver killers as they will be worth it.
Also another option (which I know some of you hate) some old school Alpine trekkers. Would be the cheapest option. Check it out OP.
On a side note who uses the quiver killers? Just wondering how well they would work with Salomon STH d14 driver cause of the toe adjustment screws?