Currently I'm mainting a couple of medium to big obj-c projects and one big ROR custom CMS. My background was mostly in Python. A few years ago this sharade of writing faster obj-c app started. You guys might have heard of Wax (in Lua) which seemed to have a similar concept to RubyMobtion (of course, w/o the shiny presentation style that comes with the ROR community). After rolling my sleeves and digging into Obj-C (and CocoaTouch), all other alternatives look like made for people who are comfy/lazy and stick to writing in high-level scripting languages. If they admit their status, no problem, just that personally I would not bet medium-to-big project on anything else except plain obj-c.
The "RubyMotion Makes Debugging Easy" is the silliest part. Good luck on using GDB/LLDB!
Note: sharade and other casual language was in no intent meant to discredit the hard work put in by the developers of such tools. Full respect for the gents behind RubyMotion. They are building a fair business.
All and all, stop whining and get to know both sides.