One thing sims can not do well at all is simulate G force +ve or -ve. Acceleration and deceleration are very good as it just tips you forwards or backwards and coupled with the visuals it feels as real (pretty much) as the plane. Is ok with turbulence, rolling into or out of a turn is also a descent effort on the sims part. Within the normal flight envelope it is very accurate with the performance, descent rates or climb rates, speeds for given power and altitude. Engine failures with damage are also ok as you feel the vibration and hear the bangs or pops. Its main goal it is very good at which is putting pilots under pressure dealing with emergency situations in real time with real (simulated) terrain and weather in the cockpit of the plane they fly.
Windshear is also pretty accurate with regards to speed loss/gain and altitude loss/gain.
Loss of cabin pressure is good as although you don't get the feeling in your ears/lungs etc you can practice the procedures with the masks. No the masks dont drop as in the cockpit you have a quick donning mask that you grab and put on your face, it is always there stowed right beside you. You do however push a button to drop the masks in the cabin (there obviously is not a cabin but you do have the button)
The way it does this is during the flight testing phase of aircraft all the data from every conceivable situation is programmed into the sim and updated with real data from situations once the aircraft is flying with airlines collected from flight recorders. They also use some wind tunnel data to put into the sim for situations beyond safe.
It is lacking once you go beyond what the test pilots dared to do when testing the aircraft as they will not do things that may result in a crash. If I got in the 330 sim tomorrow and did what the AF flight did I expect it would not behave in the same way as it is not something you do in an A330 so they have no data to put into the sim. I expect there may be an update from airbus once all the data from the black boxes is scrutinized so that the sims around the world can be more realistic in that scenario and maybe in a few months the sim will behave as the actual aircraft did.
The sim is very good for what it is intended, training pilots in normal and abnormal procedures.