If you spend your time flying within the ‘normal’ flight envelope and concentrate on the proper procedures MSFS can be considered very close in most aspects. As has been mentioned above, the control forces and ‘feel’ do not exist and so many will say that the aircraft are far to sensitive. It is merely the lack of effort required to fly that makes it seem so.
That brings me to my second point. If you attempt to fly knife edge thru Manhatten or trace the F1 track in Monte Carlo while inverted, I suggest that you will find reality takes a trip to the back of the bus. While it would be possible to do those things in real life, the 100’s of hours practicing it at altitude before ever attempting the real stunt are superceded by the 12 year old with an XBox controller using an external view to make it easier to follow the road.
REAL flying in MSFS is what you make it. If a task seems difficult, don’t adjust controller sensitivities to make it easier. Just keep practicing it until it is easier. Many maneuvers in a real aircraft are difficult to master. Not having any inertial feedback or resistance to control inputs would make those tasks much harder to master.
Many of the maneuvers and techniques that I mastered over the years, flying complex, high performance aircraft into places they were never intended to go are predicated on feelings in the hands, feet and butt. I can tell you that threading a Twin Otter into a mountain bush strip that a dozer finished creating only moments before turning final, will get your heartrate up. MSFS cannot duplicate the sweaty palms, the tightness in the stomach or the euphoric release as taxi speed is established mere feet from the pile of logs at the end of the runway.
Many of those strips are actually findable in MSFS though and I always marvel that I can find them just by following the same logging road I did 30 years ago.
How close to the real thing? Close enough that I keep booting it up.