I should say I am not an X-plane expert by any means. Even when I was keeping up with it I was fairly lukewarm and mediocre, and I haven't followed it in any real way for over a year. Neither am I an AH expert, the most I can come up with these days, due to time constraints, is an occasional foray into H2H for a merciless spanking.
Yes, Steely07, X-plane does have problems with near stall and stalled situations because it's flight model is intended primarily to simulate laminar air flow and stalled and near stall conditions are defined by their lack of laminar air flow. I have a feeling this is why loops don't 'work'. It IS possible to loop in X-plane, but some aircraft will not, and those that do often have a slight rotation near the top such that it is difficult to impossible to come down still in line with the heading you came in on. This rotation happens in some non-prop rides as well as props. For this reason, and others, I don't think this rotation is due to torque. I can manage torque in loops in AH and other sims that model torque etc. without a problem.
I have to agree with Toad that the idea of simply flying from one point to another is mindlessly boring. There are 'Virtual Airlines' for sims like X-plane where you are assigned a flight from point A to point B, and I never understood the attraction. However, for those of us who may dream of one day obtaining a pilot's license, but have never had the time and money together at the same time to actually do it, a sim like X-plane offers some interesting possibilities.
However, there are other features that do attract me. X-plane allows random failure of a wide variety of systems, not unlike taking damage from a bogey on your tail, only these failures happen without warning (you can't see the bogey coming) and there is no ctrl-D button that will tell you instantly what's busted. So you have to actually check your aircraft out to see what's wrong and what you need to do to survive.
It also allows simulation of more than 190 roll rates. You can play around with taking the Space Shuttle all the way from re-entry to the ground, or launch a Saturn V rocket, not to mention the fun of trying to turn a plane in the ultra thin atmosphere of Mars. It may not simulate all of these perfectly, but at least it tries.
X-plane also simulates more than bright sunny near cloudless summer days in Texas. It rains and snows in X-plane, visibility deteriorates, ice builds up, lightning strikes and so on. You can download real time weather data for the entire globe and fly in real time weather conditions anywhere in the world. Oh, and the water actually has waves! (They are all of a uniform size and spacing, moving at a regular rate, but at least they are there!) Landing a floatplane in the waves can actually be tricky!
Another thing I like about X-plane that no combat flight sim will ever give you because they can't force their players to work at finding a fight, is you actually have to navigate! True, you can still get a simple 'You Are Here' marker, but if you ignore that you can actually do a full IFR flight, and get lost! With the new updated terrain data they've added since I last updated I hear you can actually navigate by VFR as well.
Finally, as I implied I still prefer AH, primarily due to a fascination with WWII and it's history and the aircraft. Oh, and I also like to blow things up too, I just suck at it. Which reminds me, when is AH going to get a B-24? I want to simulate the Ploesti raids!