God bless...I can't believe I'm in this discussion again.
To clean up some smaller issues...
"Detents." I'm not an expert on the 609, but to my knowledge, it doesn't have 0-97 degrees of nacelle settings selectable by the pilot, but only some key settings representative of certain flight regimes or speeds. This isn't a flaw in either design. Long story short, the military design allows for more flexibility on the part of the pilot. Some scenarios call for use of nacelles, e.g. big changes in airspeed. Some require nose attitude, e.g. small adjustments. The military environment is tactical, and thus more dynamic than the civil one. The civil "detent" concept is probably easier to fly, but takes some control away from the pilot. The Osprey can set 0, or 60, or 90 degrees or whatever, but allows intermediate settings as the situation requires.
The Osprey doesn't auto as well as a helo. It autos well enough. It is practiced in the sim. That's no secret.
It glides decently as an APLN, and that's the preferred regime.
In a line squadron, it spends the vast majority of its time in APLN.
As others have said, it's a compromise between a helo and an airplane. It takes strengths and weaknesses from both.
The Marine Corps and Air Force have both decided that in the final analysis, those tradeoffs make sense. I concur. There will always be the corner cases where it isn't better, but in the vast majority of flight regimes, it is more survivable than other platforms. As a 46 turned 22 guy, I'll tell you that there are a lot fewer "land immediately" EPs in a V-22 than a 46.