To answer the original question, it depends on a couple of factors.

Bigger helicopters are easier to fly and thats duplicated pretty well on the sim.

What makes flying a model easier than the sim? The visual cues are much better. You aren't dependent on a little screen and with full peripheral vision you always know where the ground is, something thats easy to loose track of on a sim depending on your view settings.

What makes flying a sim model easier? The first is simple, your reset button isn't labeled VISA, you can piro flip a foot off the ground with impunity. The weather is always perfect unless you tinker with wind and stuff (which you should). The tuning and setup are always perfect though RF lets you induce failures which is also a good idea but its more perfect than not.

So whats that all mean? A simulator is a great tool. It teaches you visual orientation, and allows you to develop muscle memory. When you can know what corrections or controls to apply without thinking (use the force luke) you are well on your way. It won't teach you how to fly, how to be safe, how to know when something doesn't feel or sound right with your heli. I personally think its a waste of time trying to get it to fly exactly like your model, I think the more different models you try the better off you will be.