> RoR is great at first but in my experience quickly becomes full of hard to diagnose bugs, its magic metaprogramming seems too tempting for developers to use and leads to all sorts of problems.

I think this is true. With Rails you want to be very deliberate about who you hire (there are lots of "Advanced Beginners" out there) and how you vet and manage abstractions outside of the MVC architecture. But if you can stick to those tenets, you'll be rewarded with a very productive engineering org.