Really easy would be one of the big lama's with the coaxial system.
Being new myself, I've flown the MCPX which is a bit small to fly outside if there is any sort of breeze around. I'm setting up a 450 at the moment. I think from what I've read, and what my next build will be, it will come down to what you want to spend on the bird (helicopter not wife)
I've been looking at doing a build with an IKON flybarless system, and from what I understand is that you can set it up so that you can make a 500 bird fly almost like a coaxial one. I wanted that feature to try and dumb down the bird a bit so that the old man can fly it without too many issues, and then slowly speed it up and make it that bit more exciting