I can't speak on the Ellaroo, but I love my Diddy.
It feels very solid, and is easy to manipulate. It is the only other carrier besides my ergo that I can trust not to reek havoc on my back after hours of carrying ds. It breathes extremely well too so we don't get too hot and yet it is very pleasant in the cooler months too.
I didn't pay $200 for mine though
I bought a size 6 for $130ish.
Good-luck on your quest!