One doesn't need to do 3 hour flights, but if you are tired or frustrated after five minutes the finesse goes out the window and the techniques take a long time to acquire.
I'll echo Willy's comment about the S-55- the FDE is set up so with care I can even get it to hover in ground effect hands-off ( for short periods) and while it's not the fastest, nor the fanciest, it does allow one to get a handle on the various forces gently. Using a twist-grip stick for yaw and pitch and roll means you are constantly trying to get one hand to balance too many things and you get NO rest, let alone fighting competing forces.
I know there are many who will pop up with comments about how they fly with just a keyboard, or one hand behind their back, but that's survival, not learning or simulating. That said, in the sim, trying to learn to fly helicopters without decent controllers, in particular without rudder pedals, is like going hunting for the first time in your life by going after a grizzly bear or lion with just a K-Bar knife - it can be done but the odds are against you. Although this is mainly because it's about the cheapest to operate, as a helicopter it's at the more difficult end of the spectrum when it comes to actually flying it! Frank Robinson does keep pointing out that he didn't design it to be used for training but money talks louder.There's also the theory that learning anything at the 'difficult end' improves the skill set and makes transitioning to the 'easier' ones even easier.